Tektronix 610B Instruction Manual

Instruction Manual Models 6106, 610BR

Mul_tl&flqnge. ElecVpeters

Keithley Instruments. Inc.

26775 Aurora Road/Cleveland. Ohio 44139A216) 248-0400

MODELS 61013, 610BR ELECTROMETERS

TABLE OF CONTENTS

Section

1.

GENERAL DESCRIPTION

l-l. l-2. l-3. Differences Between the Models

l-4. Specifications. .......

l-5. Applications. ........

l-6. Accessories .........

l-7. Equipment Shipped ......

2.

OPERATION 2-1. Front Panel Controls and 2-2. Rear Panel Controls and

2-3. Input Connections ......

2~4. Preliminary Procedures. 2-5. 2-6. Current Measurements. 2-7. Resistance Measurements 2-8. Charge Measurements 2-9. Z-10. Unity-Gain Output Z-11. current source. 2-12. Static Charge Measurements. . 17 Z-13. Capacitance Measurements. 2-14. Application Notes

General ...........

Features. ..........

6108 and 610BR. .......

.............

Terminals ..........

Voltage Measurements

Recorder Outputs. ......

........

...... 9

.... 10

..... 15

......

.......

......

Page

2 3 4 4

5

5 6

6

... 8

... 13

15 17 17

.. 18

19

1 1

Section

4-6. 4-J. Grid Current Check. 33 4-a. DC Amplifier Adjustment 31 4-9.

4-10. Calibration of Ohms Ranges. 35 4-11. Meter Zero Calibration. . 3j

4-12. Accuracy Check. . . . . . 35

4-13. Drift Check . 36

5. ACCESSORIES . . . . . . 43

5-l. Model 6101A Shielded Test 5-2.

5-3. 5-4.. Model 6103A Voltage Divider 5-5. Model 6104 Test Shield. . . 44

5-6. 5-7. 5-8. 5-9.

5-10. Model 370 Recorder. . . . . . 48

Calibration Procedures. . . . 31

High-Megohm Resistor Veri-

fication. . . 35

Lead. . . . . . . . . 43

Model 61018 Gripping Probe. 43

Model 6102A Voltage Divider

Probe . . . . . . . . . 43

Model 6105 Resistivity

Adapter . . . . . , . . . 44

Models 2501 and 2503 Static

Detector Heads. . . . . . . . 45

Model 6106 Electrometer

Connection Kit. . . . . . . . 46

Model 6107 pH Electrode

Adapter . . . . . . . . . . . 4i

? :I '2 2

3.

CIRCUIT DESCRIPTION

3-l. General ...........

3-2. Voltmeter Operation

3-3. Voltmeter circuit ......

3-4. Ammeter Operation ......

3-5. 3-6. Coulombmeter Operation.

3-7. Power Supply. ........

4.

UAINTENANCE

4-l. General

4-2. Parts Replacement ......

4-3. Troubleshooting .......

4-4. Procedures to Guide Trouble4-5.

O268R

Ohmmeter Operation.

............

...........

shooting. ..........

234-Volt Ooerarion.

........

21 21

..... 21

22 24

..... 24

... 25

26 29 29

29 29

30

..... 32

6. REPLACEABLE PARTS . . . . . . . 51

6-l.

6-2. How to Order Parts. . . . . . 51

* Change Notice Last Page

* Yellow Change Notice sheet is included

only for instrument modifications affect-

ing the Instruction Xanual.

Replaceable Parts List. . . . 51

Models 6108, 610BR Replaceable

Parts List. . . . . . . . 52

Model 6108 Schematic Diagram

177953. . . , . . . . . . . 59

Green Repair and Calibration Forms . . 61

1

GENERAL DESCRIPTION

MODELS 6lOB, 610BR ELECTROMETERS

FIG

FIGURE 2.

610BR is the rack version of the Model 6108.

Keithley Instruments Model 610BR Electrometer. Model

ii

1064R

i

MODELS 6108, 610BR ELECTROMFPERS

GENERAL DESCRIPTION

SECTION 1.

l-l.

measures wide ranges of dc voltages, currente, resistances and charges. It

is a highly improved form of conventional dc vecuum tube voltmeters that ueee an electrometer tube input to provide greeter than lo14 ohm Fnput resistance. T’he Model 6lOB has all the capabilities of conventional VTVMe, but it ten also make many more measurements without loading circuits.

100 volts, 28 ~urm-ie: ranges from Lo-14

25 linear resistance ranges from 100 ohms full scale to 1014 ohms, and 15

couLomb ranges from LO-12 coulomb full scale to LO-5 coulomb.

The output stage uses a vacuum tube; othewiee.solid-state devices are used for all amplifier stages and the power supply. This increases re-

liability end stability and aLlows

l-2.

GENERAL.

a. The Keithley Model 610B Electrometer is a versatile instrument which

b. The Electrometer has 11 voltage ranges from 0.001 volt full scale to

c. The Model 6LOB input stage uses a matched pair of electrometer tubes.

FEATURES.

a. Voltmeter accuracy is Cl% of full scale, exclusive of noise and drift.

GENERAL DESCRIPTION

ampere full scale to 0.3 ampere,

greater

regulation of the power supply.

Zero drift of the Model 6108 is 200 microvolts per hour maxirmun averaged

b. over any 24-hour period after warm-up. is no more then 2 millivolts after the first hour.

c. Two amplifier outputs are available. either 23 volts or 21 milliampere for full-scale meter deflection. The current

output is variable 25% with 1.4-kilohm recorders.

output is equal to the input voltage within 50 ppm or 100 microvolts, exclusive of zero drift.

Current measurements can be made by one of two methods, the normal method

d. in which the current is determined by measuring the voltage drop across a resistor shunting the input, or the fast method in which negative feedback is appliedthrough the shunt resistor. end greatly increases the response speed on the low-current ranges.

1-3.

Model 610B. The circuits, specifications, procedures for the two models are the same. Besides the outside dimensions,

the main difference between them is the Model 6LOBR’s COARSE ZERO Control is on the front panel, not on the rear panel.

Model 610B is mentioned. Any differences are identified for the correct model.

DIFFERENCES BETWEEN THE MODELS 610B AND 610BR. The Model 610BR

a.

b. The instructions in the Manual are for both models, although only the

is

the rack

version

During the 2-hour warm-up, zero drift

A switch on the rear panel allows

The unity-gain amplifier

The latter method reduces ehe input drop

of the cabinet configuration,

electrical parts end operating

t064R

1

GENERAL DESCRIPTION

1-4. SPECIFICATIONS.

AS A VOLTMETER:

?,ODELS 6108, 610BR ELECTROMTERS

RANGE: ACCURACY:

,001 volt full scale to 100 volts in eteven Lx and 3x ranges.

?L% of full scale on all ranges exctusive of noise and drift.

ZERO DRIFT: After L-hour warm-up no more than 2 millivolts in the second hour, and in any subsequent 24-hour period, the average drift wilt not exceed 200 microvolts per hour.

HETER NOISE:

INPUT IMPEDANCE:

+tO microvotes with input shorted.

Greater than Lot4

ohms shunted by 22 picofarads on the VOLTS position of

the Range Switch. Input resistance may be selected in decade steps from LO to LOLL ohms

with the Range Switch. AS AN AMMETER: RANGE: AccuRAcY:

10-14

ampere full scale to 0.3 ampere in twenty-eight Lx and 3x ranges.

?2% of full scale on 0.3 to 10-11 ampere ranges using smattest available Ilulti-

ptiee Switch setting; 14% of full scale on 3 x tOeL2 to tOdL4 ampere ranges. METER NOISE: Less than i3 x lO-L5 ampere. GRID CURRENT: Less than 2 x lO-L4 ampere AS AN OHMMETER: RANGE: ‘KcIJRAcY: ?3% of full scale on 100 to log ohm ran es using highest available Multiplier

Switch setting;

100 ohms full scale co 1014 ohms on twenty-five Linear Lx and 3x ranges.

K4

?5% of full scale on 3 x LO9 to

to

ohm ranges. AS A COULOMBMETER: RANGE : ACCURACY: ?5% of full scale on all ranges.

LO-L2 coulomb full scale to tom5 coulomb Ln fifteen lx and 3x ranges.

Drift due to grid current does not exceed

2 x 10eL4 coulomb per second.

AS AN AMPLIFIER:

INPUT IHPEDANCE: Greater than tot4 ohms shunted by 22 picofarads on the VOLTS position

of the Range Switch.

Input resistance may be selected in decade steps from LO to LOLL

ohms with the Range Switch, OLTPUTS: Unity-gain output and either voltage or current recorder output.

Unity-Gain Output: exclusive of zero drift,

At dc,

output is equal to input within 50 ppm or 100 microvolts.

for output currents of LOO microamperes or Less.

up to one

milliampere may be drawn for input vottages OE LO votes or Less.

.*

* .

t066R .

MODELS 6108, 610BR ELECTROMETERS

GEXERAL 3ESCRI?TIO”

Voltage Recorder Output:

+3 volts for full-scale

input.

Internal resistance is 3 kil-

ohms. Output polarity is opposite input polarity.

Gain: 0.03, 0.1, etc., to 3000 Frequency Response (Within 3 db):

dc to 300 cps at a gain of 3000, rising to 25 kc

at a gain of 30, decreasing to 2.5 kc at a gain of 0.03.

Noise: 3% rms of full scale at a gain of 3000, decreasing to 1% at gains below 100.

Current Recorder Output:

tl milliampere for full-scale input, variable T5% with LLiOO-

ohm recorders. GENERAL : POLARITY: METER Switch selects left zero (positive or negative) or center-zero scales

Output polarity is not reversed. LINE STABILITY: A 10% change in line voltage will ca”se less than a LO-microvolt merer

defLection on aLL ranges. CONNECTORS : Input:

output:

POWER:

105-125 or 210-250 volts (switch selected): 50 to 1000 cps; IO Watts

uhf type; ground binding post. Voltage or current, AmphenoL 80-PCZF; Unity-gain, binding posts

DIMENSIONS, WEIGHT: Model 6108: net weight, 12 pounds. Model 610BR:

10-l/2 inches high x 6-S/8 inches wide x 10 inches dee?;

5-l/4 inches high x 19 inches wide x 10 inches deep;

net weight, 12 pounds. ACCESSORIES SUPPLIED: Mating input and output plugs; 3:2 power line adapter; binding plug.

l-5. APPLICATIONS.

a. Voltmeter applications include directly measuring potentials of vacuum tube plates and grids,

pH electrodes, piezo-electric crystals,

capacitors and electrochemical cells, and the gate potentials of field effect transistors. With the Model 2501 or 2503 Static Detector Probe, the Model 610B can measure electrostatic voltages.

b. As a picoammeter,

the Electrometer can measure mass spectrograph currents.

It can be used with photo multiplier tubes, flame and beta ray and lithium ion-drift detectors. Other uses are in gas chromatograph work, nuclear studies, plasma physic studies and vacuum studies.

Also, it can be used as a current null detector with an accurate current

reference source.

c. As an ohmeter, its uses include measuring diode characteristics, insulation resistance, and resistor voitage coefficients. With the Model 6105 Resistivity Adapter and a power supply,

the Node1 610B can measure volume and surface resistivities.

d. In addition to measuring charge directly, other coulombmeter uses are measuring charge

current over a period and obtaining integral curves of time-varying currents. The Model

6108 can measure the total energy output from a pulsed laser on its coulomb ranges when used with a calibrated photo tube or photo diode.

It also can be used as a charge ampli-

fier to measure pieza-electric crystal outputs.

1066R

3

GENERAL DESCRIPTION

MODELS 61OB, 610B~ ELECTROMETERS

1-6.

ACCESSORIES.

a. Three accessory probes, fully described in Section 5,

facilitate measurements end

extend the Electrometer’s voltage range to 30 kilovolts.

Model 6104 Test Shield is suitable for resistance measurements with either 2 or 3-

b.

terminal guarded connections, as well as voltage and current tests.

c. Model 6105 Resistivity Adapter ts a guarded test fixture for measuring volume and surface resistivitirs of materials when used with the Model 6108 and the Keithley Node1 240A High Voltage Supply.

Models 2501 and 2503 Static Detector Probes are capacitive voltage dividers with a

d.

10,OOO:l ratio, when used with the probe 3/B inch from the charged surface.

e. Model 6106 Electrometer Connection Kit contains a group of the mwt useful leads and adapters for electrometer measurements.

Model 6107 pH Electrode Adapter has a 2-Eoot cable and coaxial caxxector and accepts

f.

a Beckman and Coleman (B-C) or a Leeds and Northrup (L &N) connector.

The Adapter allows

accurate and convenient pH potential measurements with the Model 6lOB.

Model 370 Recorder is uniquely compatible with the Model 610B es well es other

g.

Keithley microvoltmeters, electrometers and picoarmneters.

The recorder is a high quality

economical instrument that maximizes the performance of the Model 6108 and many other

Keithley instruments, even in the most critical applications.

l-7.

EQUIPMENT SHIPPED.

ped with all components in place.

mating plugs for the input and output receptacles.

The Model 6108 Electrometer is factory-calibrated and is ship-

The shipping cartnn contains the Instruction Manual and

The Model 610BR is shipped with the

rgles and screws for rack mounting packed separately within the shipping carton.

FIGURE 3. Model 610ER Front Panel Controls and Terminals.

Circuit designations refer to

Replaceable Parts List and the schematic diagram.

I

0667R

MODELS 610B, 610BR ELECTROMETERS

OPERATION

SECTION 2.

2-1. FRONT PANEL CONTROLS AND TERMINALS (See Figures 3 and 4)

a.

Range Switch. range. ranges and four COULOMBS ranges.

the dial skirt.

b. Multiplier Switch. sitivity of the dc amplifier and sets the full-scale voltage range when the Range Switch is set to VOLTS. The Multiplier Switch may also be used to

multiply the AMPERES (3x maxinolm setting above LO-3), OHMS and COULOMBS

ranges on the Range Switch.

c. the instrument. OFF disconnects only the meter during recorder operation.

The + and - positions determine the polarity of the meter. sets the instrument for center zero operation (lower meter scale).

d. ZERO Controls.

Switch (outer knob) and a lo-turn FINE potentiometer (center knob). allow precise meter zeroing.

It is divided fnto a VOLTS position, 11 AMPERES ranges, eight OHMS

METER Switch. The Switch has five positions:

The Range Switch selects the measuring mode and the

The range used is indicated by an X above

The Multiplier Switch determines the voltage sen-

Two ZERO Controls are on the front panel: a MEDIUM

OPERATION

POWER OFF shuts off

CENTER ZERO

These

0764R

Circuit designations refer to Replaceable Parts List and the schematic diagram.

OPERATION

ZERO CHECK Button. Depressing the Button effectively removes all input

e.

MODELS 6108, 610BR ELECTROMETERS

signal from the instrument by shunting the input and amplifier through 10

megohms.

This allows meter zeroing on any range.

The Button is locked in

the zero check position when the line is horizontal.

f. FEEDBACK Switch.

the feedback connections within ehe instrument. made only in NORMAL. with lower input voltage drops and faster response speeds.

The FAST and NORMAL positions of the Switch determine

Voltage measurements are

With the Switch et FAST, current measurements are made

The FAST position

is also used to make guarded resistance measurements, for couLomb measurements,

and to increase response speed.

INPUT Receptacle.

!z.

connector.

A dust

The INPUT Receptacle fs a Teflon-insulated uhf-type

cap is provided.

The ground post is below the recep-

tacle.

2-2. RFAR PANEL CONTROLS AND TERMINALS (See Figure 5).

a. COARSE ZERO Switch (On front panel of Model 610BR). The COARSE ZERO Stitch has 11 positions to extend the zeroing capability of the front panel ZERC Controls.

Output Switch. The Switch fs a two-position slide switch for the output.

b.

In the 1 MA position, the instrument will drive l-milliampere recorders. In the 3 V position, the output is 3 voles for full-scale meter deflection.

Source resistance is 3 kllohms.

c. 1 MA CAL Control. The Control varies the output from 0.95 to 1.05 milliampere for 14CO-ohm recorders , so the recorder scale will correspond with the Electrometer panel meter.

OUTPUT Receptacle. A 2-terminal microphone-type receptacle provides

d.

3 volts or 1 milliampere for full-scale meter deflection. Pin no. 2 is at

case ground potential if the FEEDBACK Switch is at NORMAL.

e. Xl OUTPUT and GUARD Terminals.

The potential between the Xl OUTPUT

Terminal and the CUARD Terminal (case ground for the FEEDBACK Switch in NORMAL)

Fs eaual to the input voltage with 0.005% linearity or LOO microvolts. when the FEEDBACK Switch is at FAST, the Xl OUTPUT Terminal is et case ground end rhe,GUARD Terminal is floating.

f. FUSE.

fuse.

117-234 Switch.

g.

For 210-250 volt operation, use a L/8 ampere, 3 AC Slow Blow fuse.

For 105-125 volt operation, use a l/4 ampere, 3 AG Slow Blow

The screwdriver-operated,slide switch sets the Model

610B for 117 or 234-volt ac power lines.

h. Power Cord. The 3-wire power cord with the NEMA approved 3-prong plug

provides a ground connection for the cabinet. An adapter for operation from

2- tenninal outlets is provided. 2-3. INPUT CONNECTIONS.

a. The accessories described in Section 5 are designed to increase the

6

1064R _

MODELS 610B, 6108R ELECTROMETERS

OPERATION

PJ.wJtu 3. PlOceL OIVH liear Y*“eL m*troLs an* TerminaLs.

CLl32U

designations refer to Replaceable Parts List and the schematic diagram.

accuracy and convenience of input connections.

Use them to gain the maximm

capability of the Model 6LOB.

NOTE

Using the accessories and coaxial cables is the best way to make input connections.

b. Carefully shield the input connection and the source being measured,

since power Line Erequencies are well within the pass band of the Electrometer

Unless the shielding is thorough,

any alteration in the electrostatic field

near the Input circuitry will cause definite meter disturbances.

c. Use high resistance, Low-Loss materials -

polyethylene or polystryene - for insulation.

such as Teflon (reconrmended),

The insulation leakage resis-

tance of test fixtures and Leads should be several orders magnitude higher

than the internal resistance of the source. If it is not,

leakage Losses

will cause Lowered readings. Coaxial cables used should be a Low-noise type which employ a graphite or other conductive coating between the dielectric

and the surrounding shield braid.

Amphenol-Borg Electronics Corporation,

Hicrodot , Inc. , and Simplex Wire and Cable Company make satisfactory types.

1064R

OPERATION MODELS 6108, 610BR ELECTROMETERS

Using the Model 6LOLA Probe is a simple way to insure.good input connections.

NOTE

Clean and dry connections and cables are very important to maintain the value of all insulation materials.

Any change in the capacitance of the measuring circuit to ground will

d. cause extraneous disturbances. and tie down connecting cables to prevent their movement.

vibration is present, it may appear at the output as a sinusoidal signal and other precautions may be necessary t" isolate the instrument and the connecting cable from the vibration.

Make the measuring setup as rigid as possible,

If a continuous

e. For Low impedance measurements, adapter may be used. However, keep the leads short.

f. When measuring currents LO-l4 ampere or less with the FEEDBACK switch at FAST, some insulators - such as Teflon show up as erratic meter deflections. Insulation used in the Model 6108 is carefully selected to minimize these signals.

Connect the M"deL 610B to the circuit only when a reading is being made.

.s.

I" some cases, the grid current can charge the external test circuitry when it is connected to the Electrometer input. One example is measuring a capacitor's Leakage resistance by observing the decay of its terminal voltage. If

the

Leakage currant the terminal voltage when the electrometer is Left connected across the capacitor's terminals. that the capacitor dielectric has a negative resistance.

Techniques and applications are thoroughly discussed

in thebrochure, Electrometer Measurements, by Joseph

F. Keithley. It is available by writing to Keithley

I"stnlae"ts, 1°C.

2-4. Preliminary Procedures.

is

less than the grid

Instead, there is a build-up which seems to indicate

unshielded Leads and a binding post

may produce random signals which

current, there is

NOTE

no

decay

of

a. Check the 117-234 Switch and the Fuse for the proper ac Line voltage.

NOTE

Make sure MRTRR Switch is sst to POWER OFF before connecting

or disconnecting the power cord.

Set the controls as follows:

b.

METER Switch Range Switch Multiplier Switch FEEDBACK Switch ZERO CHECK Button

a

POWER OFF

VOLTS

1

NORMAL

LOCK

0667R

MODELS 61.0~. 610B~ ELECTROMETERS

c.

Connect the power cord and turn the XF,TER Switch to CEpiTER ZERO. Within

ten seconds, the meter pointer should come to the center zero position. If

not,

adjust to meter zero with the MEDIUM and FINE ZERO Controls.

there is no need fo use the COARSE ZERO Switch.

d. After a few moments increase the voltage sensitivity by advancing the

Multiplier Switch to .3, .L, etc.

Continue zeroing with the FINE ZERO Control.

NOTE

OPERATION

Normally,

Always turn the Model 6lOB off using the METER Switch.

shut the instrument off by disconnecting the power cord or otherwise

externally shutting off the power supply.

externally, set the Multiplier Switch to 1 or lower. cautions are not followed, the Electrometer may drift for several hours when it is used again.

e. After Long periods of storage or after an overload, the Model 610B

may drift excessively.

severe jolt can also cause a zero offset. trols. Drifting, however, can occur for a few hours.

Although the grid current of the Electrometer is much below that found

f. in conventional voltmeters, it can be observed on the meter. A small voltage results from the grid current charging the input capacity, and the Electro-

meter appears to drift when the input is open. Use the ZERO CHECK Button

to discharge the build-up.

Keep the protective cap on the INPDT Receptacle when the Electrometer is not in a circuit.

Follow the particular procedures for measuring voltage, current, re-

g. sistance and charge in the next four paragraphs.

Although the electrometer tubes

NOTE

If it w be turned off

This is corrected with the Zero Con-

Do not

If these

are

shock mounted, a

2-5. Voltugo Measurements.

a. The Model 610B’s high input impedance allows circuit measurements without causing circuit loading. For low resistance in-circuit tests, the input resistance can be Lowered to avoid pick-up problems,

NOTE

Make all voltage measurements with the FEEDBACK Switch & in the NORMAL position.

High Impedance Measurements (LO14 ohms, 22 picofarads). Follow the

b.

instructions of paragraph 2-4.

METER Switch Range Switch Multiplier Switch FEEDBACK Switch ZERO CHECK Button

t064R Y

Set the controls as follows:

CENTER ZERO VOLTS

100

NORMAL

LOCK

I

OPERATION

8fom.s 610~) 610~~ ELECTROMETERS

Connect the unknown source to the INPUT Receptacle and unlock the ZERO CHECK

Button.

Set the METER Switch to + or -, as necessary.

with the Multiplier Switch,

Recheck the zero setting after increasing the sen-

Increase the sensitivity

sitivity.

c. Low Impedance Measurements. set the Range Switch to one of the AMPERES ranges. the reciprocal of the current range. For instance, of 107 ohms

to the 10-7

Switch.

To measure sources more than 100 volts, use the Model 6102A 1O:l Divider

d.

- which is normal for conventional VTVMs - set the Range Switch

AMPERES range.

Set the full-scale voltage range with the Multiplier

Operating procedures are the same as subparagraph b above.

Probe or the 6103A 1OOO:l Divider Probe.

610B’s range to 1000 volts; 1010 ohms.

The Model 6103A extends the Model 610B’s range to 30 kilovolts;

overall accuracy is *3% and input resistance is

overall accuracy is C5% and inputresistanceis 1012 ohms. operating procedures with the dividers as in subparagraph b.

To decrease the input resistance from 1014 ohms,

The input resistance is now

to obtain an input resistance

The Model 6102A extends ths Model

Follow the same

The full-scale

voltage range is the divider ratio times the Wltiplier Switch setting.

Accuracy decreases 0.5% when the center zero scales are used because the scale span is shorter.

2-6.

Currant Mearuremantr.

The Model 610B can measure currents three ways.

a.

In the normal method - used on any range

1.

-. the current is determined by measuring the voltage drop across a resistor shunting the amplifier input. This method is useful when lower noise is more important than faster response

speeds or if some damping is needed.

In the fast method -

2.

for use only below the lO-5 ampere range the shunt resistor is between the amplifier output and input in the feedback loop.

This circuit largely neutralizes

greatly increases the response speed.

the effect of input capacity and

Also, the input voltage drop is reduced

to a maximum of one millivolt on any range.

For galvanometric current measurements,

3.

the Model 610B acts as a null

indicator between a very accurate current source and the unknown current source.

Rise time varies primarily with the currant range, theinput capacity

b.

and the method used.

50 picofarads across the input.

On most ranges, the rise time is less than one second with

Even with much larger shunt capacities, the negative feedback maintains a short rise time. Given a choice, it is better to place the Electrometer near to the current source than to the data reading instrument.

Transmitting the fnput signal through long coaxial cables greatly de-

creases the response speed and increases noise due to the cable capacitance.

c. Normal Method (0.3 to LO-l4 ampere ranges).

1. Follow the instructions of paragraph 2-4. Set the controls as follows:

10

1064R

MODELS 610B, 6lOBR ELECTROMETERS

OPERATION

METER Switch CENTER ZERO Range Switch

10-l AMPERES Multiplier Switch 1 FEEDBACK Switch

NORMAL

ZERO CHECK Button LOCK

Connect the unknown source to the INPUT Receptacle and unlock the ZERO CHECK Button. Set the METER Switch to + or -, es necessary. ity with the Range Switch and the Multiplier Switch. Switch higher then 3 for Range Switch settings lo-3 and above.

Increase the sensitiv-

Do not set the Multiplier

Check zero with

the ZERO CHECK Button.

2. The full-scale current range is the Range Switch setting times the tilti-

plier Switch setting.

Use the smallest Multiplier Switch setting possible to obtain the best accuracy. The input resistor varies with the Range Switch setting, from 10 ohms et 10-l AMPERES to lo11 ohms for lo-l1 AMPERBS.

The input

voltage drop is the meter reading times the Multiplier Switch setting.

3. On the 10-S to lo-11 AMPERES settings of the Range Switch, the high-megohm

resistors used have a voltage coefficient of a nominal y.0277 per volt.

If the

input voltage drop reaches 100 volts, en error of 100 x .02% or 2% occurs to

lower the specified accuracy. Therefore,

use a low filtiplier Switch setting

- best is 0.1 to 1 - so neither voltage coefficient nor zero stability presents a problem.

On the low current ranges, balance out the grid current

with the Zero Controls or subtract the value from the

reading. To find the amount of grid current, cap the

INPUT Receptacle and read the meter.

Fast Method (ranges below 10e5 ampere).

d.

Follow the instructions of paragraph 2-4.

1.

Set the controls as follows:

METER Switch CENTER ZERO

Range Switch 10-6 AMPERE.5

Wltiplier Switch

1

FEEDBACK Switch FAST

ZERO CHECK Button

LOCK

Connect the unknown source to the INPUT Receptacle and unlock the ZERO CHECK Button. Set the METER Switch to + or -, as necessary. Increase the sensitivity

with the Range Switch end the Multiplier Switch. Do not set the Range Switch

to 10-S AMPERES or higher. Check zero with the ZERO CHECK Button.

NOTE

Use only the ZERO CHECK Button to check zero for the

East method. Do not short the input, because this will remove the feedback from the circuit.

1264R

OPERATION

The full-scale current range is the Range Switch setting times the Multi-

2.

plier Switch setting.

smell settings permit lower current source resistance, and larger settings im-

prove instrument zero stability.

With the fast method, the input drop is reduced and the response speed

3.

is increased at least 100 times,

a) The internal impedance of the unknown current source should not be less

than .l of the value of the feedback resistor being used.

full feedback voltage cannot be developed at the input, and zero instability results.

of the Range Switch.

b) The low side of the OUTPUT Receptacle is no longer grounded. Therefore,

do not ground recorders or oscilloscopes to the Elecerometer’s case, such as

through the ground lead of the power cord.

unity-gain output (paragraph Z-10).

The feedback resistor value is the reciprocal of the AMPERES range

When selecting the Multiplier Switch setting, remember

Check the caution in subparagraph 3a below.

However,

HOODELS 610B, 610BR ELECTROMETERS

follow these cautions:

Otherwise, the

Another alternative is using the

Do not use the fast method to measure capacitor leakages.

C)

a capacitor to the input causes the circuit to be transformed into a differ-

entiator, resulting in extreme sensitivity to very smell voltage transients.

Galvanometric Method.

e.

Operate the Model 610B as a picoarmneter in the fast method of operation.

1. Use en accurate reference current source to buck out the unknown current source. Connect as shown in Figure 6.

Set the METER Switch to CENTER ZERO and use the higher current ranges.

2. Adjust the buckout current to indicate null on the l&de1 610B. Increase the

Electrometer’s sensitivity as needed.

as possible, the known reference current source equals the unknown source f

?hn Mrvi!a1 6,“R c-l,Yv-cxnr r!s,<rl,no

>

When the Model 610B is as close to null

current Source

Connecting

FIC;URE b. reference current source to buckout the unknown current source, I,. The Xodel 6LOB, on its current ranges, serves es a null detector.

fitting at the Xodel 6lOB input. with coaxial cable. graph Z-3).

12

Measuring Current by the Galvanometric Nethod. Use an *ccurs.te

Use a uhf-tee

Connect the Electrometer to the two sources

Select cable carefully for very low currents (see para-

1064R

MODELS bLOB, 61OBR ELECTROMETERS OPERATION

2-7. Resistance Measurements.

a. The Model 610B can measure resistances by three methods.

In the normal or two-terminal method (annneter-voltmeter) , the ELec-

1. trometer measures the voltage drop across the unknown sample as a known, constant current flows through it. the resistance of the sample.

The voltage drop is proportional to

This method is the simplest for the 100

to LO11 ohm ranges.

Above LOLL ohms or to prevent leakage,

2.

the guarded method is better.

It results in faster response speeds and also nullifies Leakage errors

across the Electrometer input,

since the potential across the input ter-

minal is small.

3. In the preceeding methods,

arbitrarily set.

In some cases,

the voltage across the sample cannot be

as in measuring capacitor leakage, these

methods involve much more time than if a Larger voltage could be applied.

In the external voltage method the Model 6LOB Fs used as a fast picoammeter.

The unknown resistance sample is connected to an external known voltage

source and the current through the sample is measured,

or fast method may be used.

The resistance is calculated from the readings.

Either the normal

NOTE

Discharge any capacitor before removing it from the circuit. Depressing the ZERO CHECK Button shorts the fnput through a

lo-megohm resistor, providing a discharge path.

b. Normal Method (100 to 10” ohm ranges).

1.

Follow the instructions of paragraph 2-4.

Set the controls as follows:

METER Switch Range Switch To5 OHMS Multiplier Swftch 1

FEEDBACK Switch NORMAL ZERO CHECK Button LOCK

Connect the resistance sample to the INPUT Receptacle. Unlock the ZERO CHECK Button. Check zero with only the ZERO CHECK Button,

Do not open-circuit the Electrometer on the OHMS ranges; the

input will develop a Large voltage due to its constant current characteristic. Keep the input shorted or the ZERO CHECK Button locked.

2. The full-scale ohms range is the Range

Switch setting times the Multiplier Switch setting. Use the Largest Multiplier Switch setting possible to obtain the best accuracy.

1064R

13

OPERATION

Before making a final reading, manipulate the Multiplier end Range

3.

MODELS 6LOB, 6LOBR ELECTROMETERS

Switches, so the sample is tested at a number of test potentials. The applied test voltage is the meter reading times the Multiplier SwFtch setting.

NOTE

Shield the input if the resistance sample exceeds one megohm.

Guarded Method (to 10L4 ohm ranges).

C.

Follow the instructions of paragraph 2-4.

1.

Set the controls as follows:

METER Switch Range Switch Multiplier Switch

;011 OHMS

1 FEEDBACK Switch FAST ZERO CHECK Button LOCK

Connect the low impedance side of the resistance sample to the Model 610B GUARD Terminal, and the high impedance side to the INPUT Receptacle. Unlock the ZERO CHECK Button.

2. Read the resistance as outlined for the normal method, subparagraph b. External Voltage Method (To ~016 ohms).

d.

1. Turn the ZERO CHECK Switch to L,OCK.

Connect the sample between the INPUT Receptacle and the power supply. (See Figure 7.) Put a switch in the high voltage line to ground the low impedance end of the sample when it is disconnected from the ootential.

from a known source, V, is applied to the unknown resistance sample, &. The

Model 610B measures the current through &,

lated.

Switch S grounds s when no potential Fs applied.

from which the resistance is calcu-

2. Set the FEEDBACK Switch to NORMAL. Usually this method is best, since

instabilities can arise if the resistance sample is Less than .L the value

of the feedback resistor.

3. Apply a potential to the sample before releasing the ZERO CHECK Button. Set the Range Switch to .3 AMPERES and increase sensitivity until a reading is obtained.

14

1064R

MODELS 6108, 610BR ELECTROMETERS OPERATION

4. If the potential applied is at least 100 times the full-scale input drop (Multiplier Switch setting), the resistance is equal to the applied potential divided by the current reading.

The high voltage sensftivity of the Model 61OB, therefore, permits

external voltages of .l volt or more to be used.

5. If the potential applied is less than 100 times the input drop, the resistance is e~qual to the difference between the applied potential and the input drop, all divided by the current reading.

6. If the current is read by the fast method,

need not be included in the calculation.

If the capacity shunted across the sample is

the input drop is so slight that it

large, such as encountered in capacitor leakage measurements, the fat method increases

response speed and this connection is reconrmended.

2-&Charge Measurements.

a. Follow the instructions of paragraph 2-4.

Set the controls as follows:

METER Switch CENTER ZERO

Range Switch 10-7 COULOMBS Multiplier Switch

.Ol FEEDBACK Switch FAST ZERO CHECK Button

LOCK

Unlock the ZERO CHECK Button and then connect the unknown source to the INPUT Receptacle.

If the Electrometer reads off scale, increase the Multiplier Switch setting.

If the sensi-

tivity is not enough, decrease the Multiplier Switch setting until the reading is on scale.

Changing the Multiplier Switch setting does not affect the transfer of charge from the un-

known source to the instrument. If increasing sensitivity with the Multiplier Switch does not .bring the reading on scale,

increase sensitivity with the Range Switch and repeat the

above steps.

The full-scale charge range is the Range Switch setting times the Multiplier Switch

b.

setting. Grid current contributes 2 x LO-l4 coulomb per second maximum.

NOTE

Because of the instrument’s RC time constant,

internal capacitance on the 10.’

coulomb range before making another measurement.

wait 20 seconds after discharging

On the 10-B coulomb range, wait at least two seconds.

2-g. Recorder Outputs.

a.

For recording with the Model 610B, use the Keithley Model 370 Recorder for ease, ~COUXlly, versatility and performance. The Model 370 is a pen recorder with 10 chart speeds and 1% Linearity. The Model 370’s input cable has a connector which matee directly with

the OUTPUT Connector on the Model 610B; this avoids interface problems often encountered between a measuring instrument and a. recorder. No special wiring is needed. No recorder preamplifier is required. (See paragraph 5-B Eor more on the Model 370.)

b. Other recorders, oscilloscopes and similar instruments can be used with the Model 6108.

The Model 610B has two variable gain outputs,

nals within 112% for recorders,

oscilloscopes and similar instruments.

?3 volts and *l milliampere, to amplify sig-

These can be used

on all ranges of the Model 610B.

0667R

I.5

OPERATION

MODELS 6lOB, 610BR ELECTROMETERS

c. 3-Volt output.

Receptacle. Pin no. Switch to 3 V. any range.

The Model 6lOB output is now +3 volts for full-scale meter deflection on

Internal resistance is 3 kilohms. 300 cps at a gain of 3000, gain of 0.03.

Noise is 3% rms of full scale at a gain of 3000, decreasing to 1% at gains

Connect oscilloscopes and pen recorder amplifiers to the OUTPUT

1 is the negative terminal; pin no. 2 is grounded.

Set the Output

The frequency response ($3 db) is dc to

rising

to

25 kc at a gain of 30, and decreasing to 2.5 kc at a

below 100. The METER Switch does not reverse the output polarity.

NOTE

The Model 610B may be used with the FEEDBACK Switch fn FAST position with other

instruments.

meter us3

However,

end the other instrument.

d. l-Milliampere Output.

General Electric or Texas Instrument Rectiriter, to the OUTPUT Receptacle.

the negative terminal.

make sure there is no common ground between the Electro-

Connect l-milliampere instruments, such as Esterline Angus,

Pin no. 1 is

Set the Output Switch to 1 MA.

The output is approximately 1 mil-

liampere for full-scale meter deflection on any range. For exact output, adjust the meter

on the .003-volt range with the FINE ZERO Control for full-scale deflection. Then adjust

the 1 MA CAL Control until the recorder reeds full scale.

zero end repeat adjustment if necessary.

The METER Switch does not reverse the output

Check the recorder and meter

polarity.

For servo rebalance recorders,

e.

See Figure 8.

Set the Output Switch to 1 MA.

for full-scale recorder deflection.

use a divider Operation is the same as for current outputs.

across

the Model 610B OUTPUT Receptacle.

Use the 1 MA CAL Control to trim the output

1-$

2)

Model

6108

Output

(J105)

100~millivolt output

1 kn

100 n

loo-mv

Recorder

:

FIGURE 8.

A

Model

610B

1 kn

output

*

(JlO5)

50 0

It 1

50-mv Recorder

50-millivolt output

Divider Circuits Across Model 610~ Output. The dividers are for driving 50

and 100-millivolt recorders. Use 1% resistors in the dividers.

f. When the FEEDBACK Switch is in the NORMAL position,

terminal is grounded to the instrument case.

Therefore, no difficulty will be experienced using oscilloscopes end recorders with the Model 61OB set for normal operation. position, however, neither side is grounded.

If this is used, make sure there is no com-

the negative side of the output

In FAST

mon ground between the recorder or oscilloscope end the Model 6108 case, or use the unity-

gain output.

16

;:

10&R

MODELS 6108, 610BR ELECTROMETERS

OPERATION

2-10. Unity-Gain Output. The unity-gain amplifier can be used as an

impedance matching device to minimize circuit loading errors or for convenient

connections to a recorder when the FEEDBACK Switch is in FAST position.

The unity-gain output is equal to the input within 50 ppm or 100 microvolts

a. when the load resistance is 100 kilohms or better below 10 volts or 1 megahm or better above 10 volts. By placing the Model 610B between a 1010 ohm source, for example, and a 0.01% voltmeter with a 1-megohm input resistance, overall accuracy better than 0.025% can be achieved.

1. Connect the voltmeter to the Xl OUTPUT and GUARD Terminals as shown in

Figure 9. The GUARD Terminal is at ground with the FEEDBACK Switch in NORMAL.

Maximum output amplitude is 100 volts peak-to-peak.

2. Adjust the Model 610B Zero Controls to obtain a zero-voltage reading on the instrument using the unity-gain output. Make sure the latter’s sensitivity is high enough for a precise zero adjustment. This adjustment is necessary

because a slight zero shift may occur when the Model 6108 is changed from the O.l-volt range or lower to a range above 0.1 volt. The shift, caused by a gain-reducing network switched in by the amplifier on the 0.3-volt and higher

ranges, is too slight to be read on the meter, but it can cause an error in

accurate measurements using the unity-gain output.

It 000000

‘Vx

t

cl

6108 y1

+ -

0.01% VM

V

I

GUARD

$-

FIGURE 9. Measuring Potential of High Resistance Source with 0.025% Accuracy. The Node1 6108 is used between a high-resistance source, V,, and a 0.01% voltmeter to obtain high accuracy without causing circuit loading.

The digital volt-

meter or, as above, the Keithley Model 662 Differential Voltmeter connects to

the Model 6108 unity-gain terminals.

b. When the FEEDBACK Switch is in FAST position, the unity-gain terminals per-

mit more convenient connections to recorders without special precautions. In

this mode, the Xl OUTPUT Terminal is grounded and the GUARD Terminal delivers a

full-scale output equal to the hltfplier Switch setting or the input. 2- 11, CUP.RENT SOURCE. The Model 6108 can be used as a -4% current source from

10-j to lo-11 ampere.

Set

a.

the FEEDBACK Switch to NORMAL, the Range Switch to OHMS and the DIETER

Follow these

procedures:

Switch to + or -

b. The current supplied at the INPUT Receptacle is the reciprocal of the OHWS Setting on the Range Switch. (For example, log OHMS indicates LO-9 ampere current at the INPUT Receptacle.)

c. It

does

1264R

The ,%ltiplier Switch does not affect the current at the INPUT Receptacle

afEect the maximum input voltage drop,

which is equal to the ?lultiplier

;:

OPERATION

XODELS 6108,

6tOBR EL&CTRO>IETL:{S

Switch setting. Z-12.

STATIC CHARGE MXASUREMENTS.

For accurate output current, check the meter zero on the .Ol-volt range

Electrometers are very sensitive to static charges

and can readily make qualitative or quantitative measurements.

Zero the Model 6108; set the FEEDBACK Switch to NORMAL and the Range Switch to VOLTS

(l:.or 30 volts full scale).

PDT Receptacle.

Depending upon the distance between the charge and the instrument, a voltage will be induced on the input terminals which can be read on the meter. frequently,

since accumulation of charge due to the electrometer tube grid current wilt

Bring the charged object near the uncovered, unshielded I!J-

Check zero

cause a slow drift of the inwt voltage.

b. Connecting a capaci’tor acroee the input reduces the drift due to grid current and

also the sensitivity to charge. Therefore,

set the Range Switch to COULOMBS position.

capacitor value connected across the input in farads is equal to the COULOMBS Range. 2-13. CAPACITANCE MEASUREMENTS.

The Model 610B can measure capacitance from 500 pico-

farads to LOO microfarads. The Electrometer charges the capacitor to a known potential

and then measures the charge. The resulting capacitance is easily figured.

a.

Charge the capacitor as follows:

1. Set the Model 610B front panel controls to: METER Switch

+

Range Switch VOLTS

Multiplier Switch

.OOl to 100

FEEDBACK Switch NORMAL

ZERO CHECK Button

LOCK

The

2. Connect the unknown capacitor to the INPUT Receptacle. Unlock the ZERO CHECK Button and charge the capacitor to a known voltage by setting the Range Switch to the O~DIS ranges. As the capacitor charges, the meter will advance up scale to show the voltage (meter reading times the Multiplier Switch setting) acroee the capacitor at any given time

3.

Charge the capacitor to a convenient voltage, such as 0.1, 1, 10, etc. Charge Large capacitors to a Lower voltage than that used for low value capacitors. The OHMS ranges control the charging rate: start with the Lower ranges and increase the setting as the voltage acroes the capacitor reaches the desired value.

4. When the capacitor reaches the desired value,

VOLTS position, then disconnect the capacitor from the INPDT Receptacle.

quickly set the Range Switch to the

Or, if more convenient, first disconnect the capacitor from the INPUT Receptacle, then set the Range Switch to the VOLTS position.

NOTE

Be careful handling charged capacitors.

to 100 volts.

If the capacitance is above O.OL microfarad, a dangerous potential

The Model 6108 can charge a capacitor

could exist.

b. Measure the charge on the capacitor following the instructions in paragraph 2-B

18

1066R

MODELS 610B, 610BR ELECTROMETERS

OPERATION

c. The value of the unknown capacitance is the stored charge divided by the

initial voltage:

c (farads) = Q (=‘ulo~S~

v (volts)

Z-14. APPLICATION NOTES.

The versatility of the Model 610B is such that it is almost a complete dc laboratory in itself. follow;

the purpose of these is to suggest uses and techniques to increase the

usefulness of the Model 610B.

a. current 1nceerator.

currents, Figure 10 shows the circuit.

The Model 6lOB works as an integrator for time-varying

Set the Range Switch to COULOMBS.

the unity-gain output. Output voltage, V,ut, is

T

Vout

=+

/

0

i dt

where C is the coulomb range setting in farads

610B 610B

FIGURE 10. Current Integrator. current integrator. Model 610B input.

A square wave from a current source, I,, is applied to the

Using the COULOMBS ranges, the output through the

The diagram shows the Model 610B acting as a

unity-gain terminals is shown.

Some particular applications

Xl Xl

b b

GUARD GUARD

L L

Use

b. Potentiometric Voltage Measurement%. The high input impedance, l-millivolt

sensitiv~ity and low zero drift make the Model 6108 useful as a potentiometer. The circuit shown in Figure 11 is useful when no loading of the source voltage, on or off null, can be tolerated. Make the measurements with the center zero scale, following the procedures in paragraph 2-5. When the Model 610B is at null

- no meter deflection - the voltage from the known source equals the unknown voltane.

Voltage Supply Voltage Supply

+ - + -

,

FIGURE 11. Potentiomecric Voltage Measurements. used to buck out the potential from the unknown source, V,.

An accurate voltage supply is

The Node1 610B on

the voltage ranges and center-zero scales acts as a null detector.

1264~

19

OPERATION

Measuring Diode Characteristics.

C. The Model 610B can accurately measure diode characteristics in one simple step without using any other equipment. The

circuit is shown in Figure 12. The measurements are made on the Model 610B OHMS ranges currents d&ns~~e~,“~~ z$y:n decade

steps and reading the voltage drop across the diode. The characteristic

curve can then be plotted in volts and amperes or volts and ohms. Read the voltage from the meter.

d. peak-Readina Voltmeter. The Model

610B easily converts to a peak-reading voltmeter. Set the Range Switch to

the COULOMBS ranges and apply the input voltage to the INPUT Receptacle

through an external diode. In the

circuit shown Fn Figure 13, if the input resistance (RF) and diode leakage resistance (Rd) are high and if the time constant of the RC combination is high compared to the period of the signal, the capacitor will charge to the peak value of the applied ac voltage minus the small drop across the diode. The Model 6LOB input resistance on the VOLTS or COULOMBS ranges is 1014 ohms or, greater, and may therefore be neglected compared to the leakage resistance of most diodes. The capacitor (C) Fs selected using the COULOMBS ranges with

the FEEDBACK Switch in the NORMAL position. C in farads is equal to the COULOMBS range setting.

MODELS 6 LOB , 6 LOBR ELECTROMETERS

Itl

610B

10

I

FI :Gum 12. Measuring Diode Characte

istics with Model 610B.

ranges of the Electrometer.

Use the OHMS

0

0 hl

VI

Input

.I101 c

0 ST

I

FIGURE.. 13. Diagram of Model 610B as Peak-Reading Voltmeter.

is used on its COULOMBS ranges.

is the capacitor selected with the Range Switch; Ri is the Model 610B input

resistance,

of the diode used.

20

Accuracy of the measurements depends mainly upon the quality

1 0 L

1

The diode is external to the voltmeter, C

Amplifier

. II.

and

Meter

Ri

The Model 610B

1064R

MODELS 610B. 610BR ELECTROMEl’ERS

CIRCUIT DESCRIPTION

SECTION 3.

3-1.

meter with a full-scale sensitivity of 1 millivolt and an input impedance of

LOL4 ohms shunted by 22 picofarads. resistors and capacitors are selected to make measurements over a total of 79 voltage, CUTrent, resistance and coulomb ranges. Current and resistance are measured using precision resistance standards, from lo-ohm wirewound resistors to 1OLL ohm glass-sealed, deposited carbon resistors. are measured using close tolerance polystyrene film capacitor standards.

the necessary amplifier power. 3-2.

by three differential transistor stages and a vacuum tube output stage. A

Large amount of negative feedback ts used for stability and accuracy.

Figure 14 shows the block diagram for the voltmeter mode of operation.

GEINEML.

a. The Keithley Model 61OB is basically an extremely stable Linear de volt-

A super-regulated, low voltage transistorized power supply furnishes

b.

VOLTMETER OPERATION.

a. The voltmeter amplifier has matched electrometer input tubes followed

Input

CIRCUIT DESCRIPTION

By using the front panel controls, shunt

COUlOmbS

)I-

a01 t

%

i

I

Outnut Gnd.

F1GlJR.B 14.

refer to schematic diagram.

across the amplifier.

for a given Multiplier Switch setting. e, is the voltage drop across F,,,.

3103 is the unity-gain terminal; 5104, guard.

currents within the loops.

Block Diagram of l%del 610B in Voltmeter Mode.

S106 is the &LtipLiet Switch; &,, is the resistor

Floating Gnd.

ei is the input voltage; e, is the voltage drop

Ground references correspond to schematic also.

1

I

i, and ib are

Circuit designations

fnStantaneOus

0764R

21

CIRCUIT DESCRIPTION MODELS 6LOB, 6LOBR ELECTROMETERS

When thereis no input signal and the zero is set, the current (i,) in the

b.

upper Loop of Figure 14 equals that in the lower Loop (ib): La = ib. With an

input signal,

When a positive voltage, cei, is applied to the input, the amplifier

1.

the circuit reacts as follows:

drives the V103 grid less negative, and the plate current, i,, is increased. Increasing ia Rm. At equilibrium this drop equals ei,

drop, ea,

when a negative voltage, -ei, is applied to the input, the amplifier

2.

causes a voltage drop through the E6rLtipLier Switch resistor,

and therefore, it keeps the voltage

across the amplifier to a fraction of the input voltage.

drives the VL03 grid more negative with respect to the cathode, and ia is decreased. The current in the Lower Loop, Fb, becomes greater than i,, producing a VOLtage drop, eo, across R,,,. The drop is sufficient to null the negative input voltage, ei, again keeping the voltage drop across the ampli-

fier to a fraction of the input voltage.

The voltage drop across the amplifier is

3. ea =

=i

kc1

where k is the Loop gain, approximately LO5 on the 0.001 to 0.3-volt ranges.

c. The output stage, V103, drives the amplifier ground at the same poten-

tial as the input signal. This means the ground terminal of the amplifier is

not at chassis ground, but is connected directly to the cathode of V103. Ikillg

this circuit, the input can accept voltages up to rlO0 volts without input dividers. This maintains high input impedance and eliminates instabilities

which can occur with high resistance dividers.

NOTE

On the schematic diagram, amplifier ground is called “floating ground” and the output amplifier ground, “output ground.”

All power supplies are floating with respect to the input or chassis

d.

ground. The +250 and -265 volt supplies are provided for the output voltage

amplifier, V103. Separate regulated -10 and +21 volt supplies provide power

for the amplifier and are.referred to floating ground.

NOTE

Refer to Schematic Diagram 17795E for circuit designations.

3-3. VOLTMETER CIRCDIT.

a. Two balanced 5886 electrometer tubes are at the voltmeter amplifier input. Their filaments are operated in parallel from the regulated ~21 volt supply through dropping resistors, R119 and R122. control grid of VlOl, the active electrometer tube, due to overloads.

Capacitors Cl01 and Cl10 are high-frequency bypasses. The

Resistors RlOL and R113 protect the

from excessive grid currents

control grid of VL02 is returned to floating ground,

22

1064R

MODELS 610~, 6LOBR ELECTRO~BRS

CIRCDIT

DESCRIPTION

Depressing the ZERO CHECK Button,

b. to output ground. This effectively removes all signal from the grid of VLOL, and the input impedance is reduced to 10 megohms.

c. An emitter follower stage, transistors QLOL and Q102, matches the relatively high impedance output of the electrometer tube stage to the Low input impedance of the differential amplifier stage formed by transistors 4103 and

9104. sistors QLOS and QlO6. Resistors R152 and RL53 prevent Lock-up of the amplifier under overload conditions.

Resistor RL84 protects V103 from drawing excessive grid current; capacitor Cl13 is a high-frequency bypass.

tube screen grids. The screen grids of VlOL and VLOZ are returned, in effect, to the emitters of transistors Q103 and 4104 through the COARSE

and MEDIUM ZERO Switches, SL04 and SLO5. The emitter voltage of Q103 and 9104 can vary, resulting in a negative feedback loop for signals in phase at

the electrometer tubes through the 9103 and Q104 emitter circuit back to the

VLOL and VlOZ screen grids. This connection stabilizes the electrometer plate potential and tube operating points. Also, for signals arriving at the VZOL control grid, the first stage gain will be much greater than spurious signals.

RL66, determines the voltmeter sensitivity. A l.l-milliampere current

through the resistors produces a full-scale meter deflection. On the higher

voltage ranges, resistors R171 through Rl73 are across the collectors of Q103 and QL04 to reduce the amplifier gain.

when maxiawa gain is unnecessary.

This latter stage drives a second differential amplifier stage, tran-

d. Transistor Q106 drives the grid of the output voltage amplifier, VL03.

e. The zero balance controls adjust the dc voltages of the electrometer

f. The voltage drop across the l%.zLtiplier Switch resistors, Rl56 through

SlO3, connects resistors RLOL and Ill13

This assures the amplifier stability

The recorder output is derived from the current flow from VlO3 through

8.

the ~Ltiplier Switch resistor, With the Output Switch, S108, on 3V, ?3 volts for full-scale deflection are obtained at the output connector, 3105, by r1.L

milliamperes flowing through resistor R180.

and R179 are connected across 5105, allowing 21 milliampere *5% to pass through an external Load.

h. The second triode section of V103, connected as a diode, provides warmup compensation for the -265 volt supply. conditions during warm-up and cool-down, which could cause excessive eLectro-

meter tube grid current to flow and result in poor drift characteristics.

The "normal" and "fast" referred to below are only the positions of the FEEDBACK Switch. "Normal method" is

when the Switch is set to NORMAL; "fast method" is when

the Switch is set to FAST.

1064R

With S108 at 1 MA, resistors R174

This prevents severe out-of-balance

23

CIRCUIT DESCRIPTION

MODELS 610B, 6LOBR ELECTROMETERS

.I101

Amplifier

Rs (

I

FIGURE 15.

refer to schematic diagram. for a given setting. Rs is the resistor selected by the Range Switch, SlOl. 5102 is the FEEDBACK Switch. Ground references correspond to schematic.

3-4. AMMEIER OPERATION.

a. Normal Methc.4.

Switch in NORMAL position), one of the Range Switch resistors, R102 through Rl12, shunts the input. (See Figure 15.) The Modal 6lOB than measures the voltage drop acros8 the resistor. The meter is calibrated to read the current

in amperes for the appropriate range.

Block Diagram of Model 610B as a Picoanuneter. Circuit designations

In the normal method of current measurements (FEEDBACK

.

FAST

SlO6 is the tiltiplier Switch; I&, is the resistor

?

Floating Gnd

+250 v z

L

I

-265 v C

b. East Method. in FAST position), the Model 610B functions as an The differential amplifier output is divided by the tiltiplier Switch resistors, R156 to R166, and fed back to the amplifier input through a feedback resistor selected'with the Range Switch. to the low impedance side of the input, and the output ground is floating.

method increases the

it also reduces the input drop to less than 1 millivolt. 3-5. OHhMEX'ER OPERATION.

a. NoMl Method In the normal method of resistance measurements (FEEDBACK Switch in NORMALposition), the Model 610B uses a constant-current, voltage-drop circuit. Refer to Figure 16. & is the unknown resistor. A voltage source, E, applies a potential acros8 &.

through the resistor divider network, Rll4 through Rll8.

10 volts, depending upon the OHMS range used.

between floating ground and the input grid of V103 through R,, the range re-

sistor. Rs

24

is one of the resistors, R102 through R112.

In the fast method 0f current measurements (FEEDBACK Stitch

response

anmeter

(See Figure 15.) Floating ground is connected

speed by minimizing the effects of input capacity;

The source is obtained from the +21 volt supply

The voltage source is connected

with negative feedback.

This

E varies from 0.1 to

Since feedback to the

1064R

MODELS 610B, 610BR ELECTROMETERS CIRCUIT DESCRIPTION

floating ground keepa the grid et nearly the same potnetial as the cathode, the current, I, through Q and Rs is constant. of the value of G,, as long as the voltage drop across R/ does not exceed the Multiplier Switch setting. the input.

indicate the resistance value on its calibrated meter.

The Model 610B can then measure the voltage drop across Rx and

This circuit provides a true source regardless of

I is equal to E/R,, regardless

+25ovz

I

t

I I

Amplifier

Output Gnd

I (

1

I

1

FIGURE 16. Block Dianram of Model 610B for Normal Method of Measurine Re-

sistance. Circuit designations refer to schematic diagram. mltiplier Switch; R,,, is the resistor for a given setting. known resistance being measured; E is the voltage source (see paragraph 3-5);

R, 1s the range resistor selected with the Range Switch.

correspond to the schematic.

b. Guarded Method In the guarded method of resistance measurements (FEED-

BACK Switch inF&ition and the sample resistance connected between the

input terminal, JlOl, and the guard terminal, J104), feedback is applied through the sample. Refer to Figure 17. The circuit is similar to the normal method, except for the feedback. This reduces the slowing effect of the instrument's

input capacity. input terminal is small.

low impedance side of the input and the output ground is floating. terminal is at output ground porenfial.

Leakage error is also reduced since the potential across the

In this mode, floating ground is connected to the

SlO6 is ;he

G is the un-

Ground references

The guard

3-6. similar to that used for an annneter with the fast method. A negative feedback is applied around a shunt capacitor, Cl03 to C106, selected with the Range

Switch. is proportional to the voltage across the capacitor, which is measured by the Model 610B voltmeter circuits.

1064R 25

COULOMBMETER OPERATION.

The shunt capacitor replaces R, in Figure 15. The stored charge

The Model 610B circuit for measuring charge is

CIRCUIT DESCRIPTION

MODELS 6108, 610BR ELECTROMETERS

FIGURE 17. Block Diagram of Model 610B for Guarded Method of Measuring Resis-

tame. Circuit designatfons refer to schematic diagram.

Switch; R, is the resistor for a given setting.

G is the unknown resistor being

5106 is the Multiplier

measured; E is the voltage source (see paragraph 3-5); R, is the range resistor

selected with the Range Switch. 5104 is the GUARD terminal. Ground references correspond to the schematic.

3-7. POWER SUPPLY.

nishes +250,

a.

A 24-volt

-265, +21 and -10 volts to the differential amplifier.

rectified by diodes D203 end D204 and is filtered by capacitor C204.

The power supply operates from the line voltage and fur-

rms output

from the power transfomer, T201, is full-wave

The dc

voltage across C204 is approximately 30 volts dc.

b. To obtain a stable, accurate voltage, the output of the series trms-

istor, Q202, is regulated by comparing e sample voltage from dividers R212

and R214 to the zener diode reference, D210.

If e voltage difference exists,

ft is amplified by a differential amplifier consisting of transistors 4204 and 4205. The Si@‘ld is further amplified by transistor 4203. The output of 4203 is applied to Q202 to nullify input and load variations. Capacitor C208 prevents high-frequency oscillations.

The +21 volts at the output of the regulator powers the amplifier, the filament of the electrometers, and is used as the reference supply for the OHMS ranges.

c. Transistor 4203 operates at a high gain by conneceing its collector load

to a negative regulated supply. The circuit permits linear operation of Q202

with widely varying input voltages. To supply Q203, a 50-volt output of trans-

former T201 is half-wave rectified by diode D201 and is filtered by capacitors C203 and C205. Resistor R201 is a dropping resistor. The voltage across the zener diode D202 is a stable -10 volts, which is supplied to resistor R209, the collector load resistor of 9203, and the differential amplifier.

26 1060

MODELS 6LOB, 610BR ELECTROMETERS

Transistor 4201 is an emitter follower whose function is to increase the

d.

current gain of the series transistor,

4202, forming a Darlington pair.

CIRCUIT DESCRIPTION

Resistors R208 and R209 and diode D208 provide current overload protection. Excessive current drawn from the power supply causes an increased voltage drop across R208, which forward biases diode D208, thus preventing the collector of Q203 from going more negative. Since the collector voltage cannot rise, further amplification is prevented and, therefore, further current increase is prevented.

e. The ~250 volts and -265 volts for the output stage are obtained from a single winding on transformer T20L. 210 volts from the transformer is half-wave rectified by diodes D205 and D206, and filtered by capacitors

C206 and C207, respectively.

Resistor R203 provides short-circuit protection;

resistor R204 discharges the capacitors when the instrument is turned off.

1064R

MODELS 6108, 6106~ ELECTROMETERS

SECTION 4.

4-1.

the Model 610~ Electrometer. ly as possible to maintain the accuracy of the instrument.

high-quality electronic equipment. The value of the high-megohm resistors, R110, RI11, R112, should be checked every two or three years for specified accuracy. AlSJ, amplifier balance requires occasional adjustment; see paragraph 4-8.

4-2. PARTS REPLACEMENT.

Electrometer. meet the specifications.

from Keithley Instruments, Inc. In normal use, 10,OpO hours of operation. They can be checked only by replacement. Standard 5886 tubes could be used in an emergency, but the drift, noise and grid current specifications may

not be met. When replacing the electrometer tubes with a matched set from Keithley, fur-

ther ageing of the tubes within the Model 6106 is required; a minimum of 3 days is recommender

GENERAL.

a. Section 4 contains the maintenance,

It is recommended that these procedures be followed a5 cLos?-

b. The Model 6108 requires no periodic maintenance beyond the normal care required of

a. The Replaceable Parts List in Section 6 describes the electrical components of the

Replace components only as necessary.

b. The electrometer tubes, VlOL and VlO2, are specially matched and aged; order only

MAINTENANCE

troubleshooting and calibration prticedures for

the dc

Use only reliable replacements which

they should not need replacement before

NOTE

When replacing the electrometer tubes, do not touch the glass base where the

leads emerge. Increased leakage will result from any contamination.

c. Transistor pairs QlOl, Q102 end Q103, QlO4 are matched for dc current (hFE). Order

only Ecom Keichley Instruments, Inc.; replace only as a pair.

4-3. TROUBLESHOOTING.

a. The procedures which follow give instructions for repairing troubles which might

occur in the Model 6108.

parts. Table 1 lists equipment recommended for troubleshooting.

Instrument

dc voltmeter,

input resistance, Erom one volt to 300 volts.

Tektronic Type 561A Oscilloscope Observe wave forms in

TABLE 1. Equipment Recommended for Node1 610B Troubleshooting. or their equivalents.

with minimum 100-megohm

LO% accuracy, range

Use the procedures outlined and use only specified repl.acement

If the trouble cannot

Use

Circuit checking

power supply

Use these instruments

1066R

‘9

MAINTENANCE

MODELS 6108, 610BR ELECTROMETERS

c

,

Difficulty

Excessive zero drift.

Excessive grid current.

microphonics. Defective electrometer

Cannot meter zero on any range.

Meter

Multiplier Switch

setting.

10-l’ to lo-l4 ampere current ranges are out of specifications.

TABLE 2.

will not zero on

i.fodel 610B Troubleshooting.

I

Probable Cause

Electrometer tubes may be

defective.

DC amplifier not balanced. Check per paragraph 4-8 Excessive humidity or

&bfEctive electrometer

See paragraph 4-4.

Faulty resistor for set-

ting of mltiplier Switch.

Defective high megohm resistors.

See paragraph 4-2 for checking VlOl and V102.

I

Check VlOl and VlO2; replace if faulty.

Check VlOl and V102; replace if faulty.

I

Check VlOl and V102; replace if faulty.

I

3ee paragraph 4-4.

Check resistors; replace ff faulty.

Check per paragraph 4-9.

Solution

-

‘.

d

be readily located or repaired, Keithley Instruments, Inc., can service

the fnstrument et its complete service Facilities. Contact your nearest representative.

Table 2 contains the more conrmon troubles which might occur. If the re-

b. pairs indicated in the table do not clear up the trouble, find the difficulty through a circuit-by-circuit check, the circuit description in Section 3 to find the more critical components and to determine their function in the circuit.

177953, is found in Section 6.

4-4. PROCEDURES TO GUIDE TROUBLESHOOTING.

If the instrument will not operate, check the fuse, line cord and power

a. source. If these are all found satisfactory, use the following procedures to isolate the trouble.

The schematic diagram indicates all tube element voLtages.and transistor

b. terminal voltages referenced to floating or output ground; check Notes on the diagram. Multiplier Switch at 1, and the meter zeroed. Measurements are with a LOO-megohm dc voltmeter.

c. At times, Adjust the COARSE ZERO Switch, S104 (Figure S), balance. If this does not work, continue to check the circuits.

The control settings Eor these values are the Range Switch at VOLTS,

the meter will not zero on any range with the input shorted.

such as given in paragraph 4-4. Refer to

The complete circuit schematic,

to bring the Model 610B into

30

--r

1064R

MODELS 6108, 610BR ELECTROMETERS MAINTENANCE

Check the filaments of the electrometer tubes, VLOL and V102, by measur-

1. ing the voltage drop across the filament dropping resistor, Rll9 (Figure 22). IF both filaments are operating properly,

the voltage will read 2.0 volts dc

?lO%.

Check the output tube, V103 (Figure 23 ), to see that both filaments

2.

are lit.

Inspect the leads from the shock-mounted input printed circuit board,

3.

PC-84, to the amplifier printed circuit board, PC-85, for possible breaks.

d.

Su~oly. Power

1. Set the FEEDBACK Switch to FAST to connect the instrument's chassis to floating ground. supply and the chassis.

Connect a 100~megobm dc voltmeter between the -10 volt

(-10 V is indicated on PC-86, Figure 18.) The

voltage should be -10 volts dc 220%.

2. Connect the voltmeter between the +21 volt supply and the chassis. (~21 V is indicated on PC-86, Figure 18.) The +21 volt supply can,not

operate unless the -10 volt supply is operating. ~'21 volts dc 210%.

A faulty ~21 volt supply can indicate a faulty zener,

The voltage should be

D210 (Figure 23).

Check the +2SO end -265 volt supplies; these should be correct within

3.

10%.

For this measurement, use output ground as the co@anon connection for

both supplies.

Amplifier.

e.

To check the amplifier, disconnect the feedback 150~ by removing the

1.

output tube, V103. This allows each stage of the amplifier to be individual-

ly checked.

It also eliminates the possibility of applying excessive voltage

to the electrometer tube grids, causing serious damage.

NOTE

Use a LOO-megohm dc voltmeter as a null detector to check the amplifier

stages.

2.

Adjust the COARSE and MEDIUM ZERO Controls for null.

Do not ground its low side.

Connect the voltmeter between the plates of VlOl and VlO2 (Figure 22).

If a null cannot be

reached, check VlOl, V102, the COARSE end MEDIUM ZERO Control circuits

(resistors R128 to RlSl), and transistors QlOl and Q102. Check the tran-

siscors by removing them and adjusting for null again.

replace the transistor pair with a new pair.

ed,

Check the next stage by connecting the voltmeter across the emitters

3.

lf null is now reach-

of QlOl and 9102 (Figure 21) end adjusting the COARSE and MEDIUM ZERO

Controls for null. If a null is not reached, check this stage end the base

circuit of the next stage. Check the base circuit by removing transistors 9103 and 4104 end again adjust for null. If null is now reached, replace the transistor pair with a new pafr.

1064~

31

MAINTENANCE MODELS 610B, 610BR ELECTROMETERS

Check the next stage by connecting the voltmeter across the collectors

4.

of 9103 end Q104 (Figure 21), end adjusting the COARSE and MEDIUM ZERO Controls

for null.

base circuit of Q105 and QlO6.

5.

the FINE ZERO Control for null.

operating correctly and the trouble is in the output stage or the feedback stage.

6.

citor, Cl13 (Figure 23), for a possible short.

7.

the recorder output resistors, R180 on 3V position

position, ing of the meter. An open multiplier resistor, however, prevents zeroing

for only that particular multiplier setting.

If a null is

Connect the voltmeter across the collectors of Q105 and Ql06. Adjust

Check the output stage cathode resistor, Rl8S (Figure 24)) end capa-

The feedback Loop includes the multiplier resistors, RlS6 through Rl66,

and the meter.

not

reached, check this stage and for shorts in the

If null is reached,

An opening of any of these components prevents zero-

the dc amplifier is

or

R174 and R179 on 1 MA

4-s. power source unless otherwise ordered.

use a screwdriver to change the slide switch on the beck panel to 234.

the fuse from l/4 To switch from 234 to 117-volt operation, reverse the procedures.

4-6.

the mdel 610B.

are not avaflable or if difficulty is encountered, contact Keithley Instruments,

Inc., or its representatives to arrange for factory calibration.

fier balance adjustment, high-megohm resistor verification, calibration of the ohms ranges, meter zero calibration and

Keithley Instruments Model 241

Regulated High Voltage Supply

Keithley Instruments Model 261 Picoampgre spurce* fr#m LO-L4 to LOe4 ampere,

234-VbLT OPEBATION.

ampere

CALIBRATION PROCEDURES. The following procedures are recoranended for calibrating and adjusting

'a.

Use the equipment reconrmended in Table 3. If proper facilities

b. Procedures

Check grid current (paragraph 4-7) et regular intervals to make sure

1.

the electrometer tubes are functioning

0 1.5/,.

are

covered for the following: grid current check, dc ampli-

Instrument

The Model 610B is shipped for use with a 117-volt

To convert

to l/8 ampere. No other adjustment is necessary.

accuracy

correctly.

Calibrate meter zero and verify

voltage range accuracy. Calibrate current, resistance

and charge ranges.

it

for 234-volt sources,

check.

Use

Change

Keithley Instruments Model 370 Recorder

Keithley Instruments Model 515

Megohm Bridge

KeTCh1eyRrsrrnment.s Model 662

TABLE 3. ments or their equivalents.

32

Equipment Recommended for Model 610B Calibration. Use these inetru-

Zero drift check.

Verify high-megohm resistors in Range Switch.

Calibrate resisrmrre-ranges

and meter zero.

0667R

MODELS 610B, 610BR ELECTROMETERS

Control

MAINTENANCE

Circuit

Designation

Ohms Calibration

Meter Center Zero Calibration

Meter Calibration DC Amplifier Balance

TABLE 4. Model 610B Internal Controls.

Rll5 18 4-10 R167 R175 RL77

18 4-11 18 4-11 19 4-8

The Table Lists all internal controls,

the figure picturing the location and the paragraph describing the adjustment.

2. The dc amplifier balance adjustment (paragraph 4-8) is necessary about

every six months or when amplifier components are replaced.

3. Verify the value of the high-megohm resistors (paragraph 4-9) about

every six months to check on drifting.

4. Calibrate the ohms ranges (paragraph 4-10) about once a year or when

range resistor or power supply components are replaced.

5. Calibrate the meter zero (paragraph 4-11) about once a year or when

components are replaced.

Check the Model 610B (paragraph 4-12) once a year, after the other

6.

adjustments, or if improper operation is suspected.

c. If the tide1 610B is not within specifications after the calibrations and adjustments, follow the troubleshooting procedures or contact Keithley Instruments, Inc.,

or its nearest representative.

4-7. GRID CURRENT

CHECK.

Check grid current whenever excessive noise or drift

is suspected. To read the grid current of the Model 610B, set the front panel

controls to:

METER Switch

+ tiltiplier Switch .Ol Range Switch

ZERO CHECK Button

FEEDBACK Switch

Cap the INPUT Rece

less than 2 x 10-L

tacle.

e

ampere. If this is exceeded, check the +Zl volt supply

The grid current indicated on the meter should be

10-11 AMPERES Unlocked FAST

and the electrometer Tube, VlOl. 4-8.

DC AMPLIFIER BALANCE ADJUSTMENT.

an occasional adjustment of the amplifier balance.

components are replaced.

This adjustment sets the gain to allow the meter to

Gradual aging of components may require

Also adjust if amplifier

receive the correct signal on all ranges.

1064R

33

MAINTENANCE

MODELS 610B. 6lOBR ELECTROMETERS

FIGURE 18.

Model 610B Internal Controls.

+21 volt power supplies are also shown.

Test points for the -LO volt and

Refer to Figure 19 for the DC AMP

BAL Control.

a. Set the front panel controls to:

METW Switch

Multiplier Switch Range Switch ZERO CHECK Button FEEDBACK Switch

CENTER ZERO

0.1 VOLTS

LQCK

NORMAL

Zero the meter on the 0.1~volt range.

b. Connect the floating Model662 across the collectors of transistors QlO5 and Q106 (this is across the ends of resistors Rl81 and R182, Figure 21). Make the connections from the component side of the printed circuit board.

Float

the Model 662 ground terminal.

c. Adjust the DC AMP BAL potentiometer,

R177 (Figure 19)) until the meter

shows a null. 4-9. HIGH-MEGOHM RESISTOR VERIFICA!l!ION.

a. About every six months, it is necessary to check the value of the high-

megobm resistors, RllO to R112, on the Range Switch.

The instrument should be

within its rated accuracy for two or three years from the time It leaves the

factory. After this, smne of the resistors may drift cut of tolerance and should

be replaced.

Faulty high-megohm resistors will affect the accuracies of measure-

ments for the 10-9 to LO-LL AMPERES and the LOB to 10L2 OHMS settings of the

Range Switch.

MODELS 610B, 6lOBR ELECTROMETERS

MAINTENANCE

To check these

resistors

thban 1% accuracy up to 1011 oh&.

it is necessary to use a bridge capable of better

An accurate megobm bridge, such as the Keithley Instruments Model 515 Megohm Bridge which is accurate to 0.25% for these ranges, is therefore necessary.

cedures

are

recommended to check out the resistors:

Return the complete instrument to the factory for resistor calibration.

1.

If such equipment is not available, two pro-

2. Replace the high-megohm resistors periodically with a certified set

from Keithley Instruments to assure absolute calibration accuracy.

4-10.

CALIBRATION OF Om RANGES.

power supply needed for resistance measurements.

This calibration adjusts the constant

It must be accurate to

maintain specified resistance measurement accuracy.

Connect the Model 662 to the junction of resistors RlL5 and R116 (Faigure 24) and the conrmon lead to the + terminal of capacitor C203 (Figure 23). Adjust the OHMS CAL potentiometer, RlL5 (Figure 18), for 10

volts dc 20.5%.

If the control does not have enough latitude, check the -21 volt

b.

supply (paragraph 4-4). 4-11. METER ZERO CALIBRATION.

Check meter zero whenever components are

replaced or other adjustments are made.

a. Turn the METER Switch to METER OFF.

Set the mechanical Zero Meter adjust-

ment for zero meter reading (top-scale zero).

b. Turn the Model 610B on.

Zero the meter on the .OOl-volt range. Then

switch to the LO-volt range. Set the Multiplier Switch to 10; apply 10

volts ?0.05% to the tide1 6108 INPUT Receptacle. Adjust the METER CAL

potentiometer, R175 (Figure 18), for full-scale meter reading.

Set the center zero by first zeroing the meter on the .OOl-volt range.

c. Then switch to the l-volt range. Set the METER Switch to CENTER ZERO and adjust the CENTER ZERO CAL potentiometer, R167 (Figure 181, for exact

center-scale meter

4-12.

operation;

ACCURACY CHECK.

a.

Checking the accuracy is the quickest way to spot improper Electrometer

Perform the check about once a year, if components are replaced,

or if other adjustments made.

zero.

If accuracy is verified over all ranges,

the Model 610B should be able to meet all specifications. If the accuracy

must be checked often, check for zero drift.

b.

Voltaee.

Connect the Model 610B to the Model 241 Power Supply. First,

set the Model 610B for the lo-volt range. Increase the input voltage in l-

volt steps.

full scale.

The Model 610B should indicate the input voltage to ?l% of

Check the other voltage ranges for accuracy at full scale.

Current.

c.

Connect the Model 610B to the Model 261 Picoampere source. Check the full-scale accuracy of all current positions on the Range Switch, For the

1 to lOA

ampere ranges,

set the FEEDBACK switch to XORMAL.

For

066iR

35

MAINTENANCE

MODELS 6108, 610BR ELECTROMETERS

the 1O-5 to lo-l1 ampere ranges,

set the FEEDBACK Switch to FAST.

The Model

6108 should indicate the input current to ?2% of full scale from the .L to 10-B ampere ranges,

%% of full scale from the 10-g to IO-l1 ampere ranges.

d. u. All resistance ranges will be within specifications if the current

ranges are within specifications and if the ohms range calibration (paragraph

4-10) is correct.

coulombs. Set the FEEDBACK Switch to FAST and the tiltiplier Switch

e.

to 3.

Use the current source to provide an input current. With the Range

No other procedures are necessary.

Switch set to the COULOMBS ranges given in Table 5, apply the corresponding input current. Use a stop watch to time the rise to full-scale deflection.

Minilmml

COULOMBS Range

(Range Switch)

Input Current Rise Time To Model 610B (Zero to Full Scale)

10-7 10-B ampere 30 seconds 10-B 10-g 10-10

TABLE 5.

Coulomb Ranges Accuracy Check, The table gives the input current

10-g ampere 30 seconds 10-10 ampere 30 seconds 10-11 ampere 30 seconds

needed to check the rise time for each coulomb range.

4

4-13. DRIFT CHECK.

Refer to the accuracy check before performing the drift

check.

Set the front panel controls to

a.

METER Switch + tiltiplier Switch

.03 Range Switch VOLTS ZERO CHECK Button LOCK FEEDBACK Switch

NORMAL

Set the Output Switch on the back panel to 3 V.

Connect the Model 610B OUTPDT Receptacle to the Model 370 Recorder.

b.

recorder to 1 volt.

Make sure the Model 610B chassis cover is attached with

Set the

at least two screws.

Make the drift run for at least 24 hours.

c.

The zero drift specification is 200 microvolts per hour maximum averaged over any 24-hour period after warm-up; during two-hour warm-up, no more than 2 millivolts after the first hour(Refer to

Chart 1).

Change electrometer tubes if the instrument does not meet the zero drift

d.

specification.

36

1066R

X~DELS 610B, 610BR ELECTROMETERS

NAINT'ZNILUCE

CHART 1. Typical drift run of Keithley Model 610B.

of the Electrometer. second hour.

In any subsequent 24-hour period,

After l-hour warm-up the drift is no more than 2 millivolts in the

the average drift will not exceed 200

microvolts per hour.

The drift run shows the stability

0166R

FIGURE 19.

Side View of Model 610B Chassis.

Front panel faces right.

of components, printed circuits and switches is shown.

for circuit designations.

Figure 20 shows ehe opposite side.

Location

Refer to the Parts List

37

MAINTENANCE

MODELS 6108, 610~~ ELECTROMEXERS

~rinced tircuir 86

23, 24

FIGURE 20.

Side View of Model 610B Chassis. Front panel faces left. Locatfon of components and printed circuits is shown. circuit designations.

Figure 19 shows the opposite side.

38

Refer to the Parts List for

1064R

XODELS 610B, 610BR, ELECTROMETERS

HAINTEXANCC

si. ‘& ; ~

1.

.

FIGURE 21. Component Locations on Printed Circuit 85.

,’ ,, ,;.,o

i &:,~3

FIGURE 22 (left). Printed Circuit 84.

Component Locations on

The red dots on VlOl

and V102 are toward each other.

MODELS 6108, 610BR ELECTROMETERS

RIO5

MAINTENANCE

FIGURE 25. Component Locations on Range Switch, SlOl. high-megohm resistors.

Capacitors Cl03 and C104, not shown, are parallel to

capacitors Cl05 and C106.

RI12

Cl02

Figure 26 shows the

\

1064R

FIGURE 26.

Component Locations on Range Switch, 5101.

shows the other components.

Figure 25

MAINTENANCE

MODELS 610B, 610BR ELECTROMETERS

FIGURE 27. Component Locations of MEDIUM and FINE ZERO Controls. Also refer to Figure 28.

Rl’jl

FIGURE 28. Component Locations of MEDIUM and FINE ZERO Controls. Also refer to Figure 27.

R147

RI46

42

Rlj7 Rl58

Rl59

FIGURE 30. of lbltiplier Switch, SlO6.

Also refer to Figure 29.

Component Locations

1064R

MODEL 6108, 610~R ELECTRO~TERS

I

SECTION 5. ACCESSORIES

hCCESSORIES

5-1.

more convenient.

with 30 inches of low-noise cable terminated by a uhf-type plug. The plug connects direce-

Ly into the Node1 610B INPUT Receptacle.

Its operation with the Model 610B is explained in paragraph 2-5. 5-2.

meaSulementS. The gripping feature is useful for attaching the probe at a single point :~r

repeated measurements.

plug. 5-3.

can be used with the Model 6108 up to 1000 volts with an accuracy of 3%.

nished with 30 inches of low-noise cable,

Model 6102A with the Model 6108 are given in paragraph 2-5.

MODEL 6101~ SHIELDED TEST LEAD.

a.

The Model 6101A is a prbbe and shielded Lead to make measurements with the Xodel 6i’?B

It does not alter any Node1 610B specification. The Lead is furnished

b. Using the Model 6101A Lead insures better input connections (see paragraph J-3)

MODEL 61018 GRIPPING PROBE.

It is furnished with a 30-inch cable that is terminated with a uiir

The Model 61016 connects directly into the Model 6108 INPUT Receptacle.

MODEL 6102~ VOLTAGE DIVIDER PROBE.

a.

The Model 6102A is a LO:1 voltage divider with an input resistance of 1010 ohms. it

b. The plug connects directly into the INPUT Receptacle.

The Model 6lOlB is a gripping probe to permit fast, easy

‘The Probe is fur-

terminated by a uhf-type plug.

Instructions for using the

FIGURE 3L.

5-4.

It can be used with the Node1 6108 up to 30,000 volts. decreasing to :Lo% at 30 kilovolts, cable,

using the Xodel 6103A with the 4lodel 6108 are given in paragraph 2-5.

HODEL 6103A VOLTAGE DIVIDER PROBE. The ~lodel 6103A is a 1OOO:l voltage divider with an input resistance sf 10Lz ohms.

a.

The plug connects directly into the Node1 6108 INPUT Receptacle.

b.

Keithley Model 6101A and 6102~.

terminated by 3 uhf-type plug.

Both Xodels have identical external appearance

Accuracy is =5X to 15 kilovolt;.

The Probe is furnished with 30 inches of low-noise

Instructions for

ACCESSORIES

MODELS 610B, 610BR ELECTROMETERS

Model 6103A 1OOO:l Voltage Divider Probe.

5-5.

FIGLIRB 32.

MODEL 6104 TEST SHIELD.

a. The Model 6104 is useful for making guarded measurements or to avoid pick-up problems. or three-terminal connections.

For resistance measurements, it can be used with either two-teminal

The Model 6104 is also suitable for voltage and

current tests.

2-Terminal Operation.

b.

Connect the high-impedance side of the test sample to the Model 6104

1.

INPUT terminal. Connect the low-impedance side to either black jack marked

GROUND, whichever is more convenient.

Lock the enclosute and connect the mdel 6104 bnc-type receptacle to the

2.

Model 6LOB INPUT Receptacle.

Use a short coaxial cable lead.

Operate the

Electrometer as explained in Section 2. c. 3-Terminal Operation.

For guarded measurements,

1.

make the connections as above with some

additional steps.

Connect the Ebdel 6104 black external plug to the Model 6lOB GUARD terminal.

2. Connect either terminal marked EXTBBNAL SOURCE to the test sample at

3.

its high-impedance side. Lock the enclosure and connect the Model 6104 to the Electrometer.

Connect the external power source to the l@del 6104 banana plugs, positive

4.

to red and negative to black.

5-6.

MODEL 6105 RESISTIVITY ADAPTER.

Operate the Electrometer as explained in Section 2.

a. The Model 6105 is a guarded test fixture for measuring resistivities of

materials in conjunction with the Node1 6LOB and the Model 240A Regulated High ;Jl:"~l;~gPlY.

The complete system directly measures volume resistivities up

ohm-cm and surface resfstivities up to 5 x 1018 ohms, in accordance

with the procedures of the American Society for Testing and Materials. The

shielded Model 6105 is a means for maintaining good sample contact with uniform

44

0268R ~,

MODELS 610B, 610BR ELECTROMETERS

ACCESSORIES

FIGURE 33. Model 6104 Test Shield.

FIGUU 34. Elodel 6105 Resistivity Adapter

pressure. The Adapter holds samples up to 3.5 inches in diameter and .25 inch thick. Maximum excitation voltage is 1000 volts.

The model 6105 Instruction Manual fully explains the operating proce-

b.

dures for the system, using the Models 24.0A and 6108.

c. The Model 610B alone can also be used with the Model 6105. Operate the

Model 6lOB as a constant current source (paragraph 2-11) with the FEEDBACK

Switch in FAST position. Connect the GUARD Terminal on the rear panel to the center terminal of the Model 6105 Power Receptacle. procedures are as for the 3-unit system.

The current from the Model 6lOB

Other operating

is the reciprocal of the OHMS setting of the Range Switch; the voltage is the Multiplier Switch setting times the meter reading.

j-7.

NODELS 2501 AND 2503 STATIC DETECTOR HEADS.

a.

The Model 2501 is a lO,OOO:l capacitive voltage divider when used with the head 3/8 inch from the charged surface. Measurements are accurate within 10%. The Model 2501 consists of a 3-inch diameter head and 10 feet of

cable.

It connecta directly into the Model 610B.

The Model 2503 is a similar probe. The difference between them is the

b. Hodel 2501 has a 3-inch diameter head and the Model 2503, l/2-inch diameter head.

0268R

ACCESSORIES

MODELS 610B, 6LOBR ELECTROMETER

The Models 250/2501 Instruction Manual fully explains

c.

the system.

I

4

5-g. MODEL 6106 ELECTROMETER CONNECTION KIT.

a. The Model 6106 Kit contains a group of the most useful Leads and adapters.for use in electrometer measurements with the Model 6LOB. wide x 8 inches deep with polyethylene foam compartments. pounds.

FIGURE 35.

Model 2501 Static Detector Head.

The kit case is 2 inches high x 12 inches

the operating procedures for

It weighs approximately three

The Kit contains two Leads made with 30-inch low-noise coaxial shielded cable (RG

b.

58A/W. clips for connection to the circuit under test, Table 2 for model numbers.)

c.

ed together, a uhf "tee" connector, and a bindlng post adapter.

Fig. 36

t

One lead has a uhf plug for connection to the electrometer, and two alligator

The second lead has two uhf plugs. (See

Adapters are also supplied for uhf-to-bnc conversion.

Other accessories include two uhf female couplers which permit cables to be connect-

Item

Description

1 Test Lead, two uhf plugs 2 3 Two Connectors, female uhf to female uhf

4

5 6

7

Binding Post Adaptor, uhf pLug HodeL 6106-2 Two Connector Adaptors, female uhf to male bnc

connector, male uhf to female bnc Connector Adapter Tee,

Test Lead, uhf plugs and two alligator clips Model 6106-L

TABLE 6. Contents of Hodel 6106 Electrometer Conneccian Kit,

two male uhf and one female uhf

Keithley Part No.

. 18265C

cs-5 CS-172 CS-115

cs-171

46

3268~

MODELS 6108, 610BR ELECTROMETERS

j-9.

MODEL 6107 pH ELECTRODE ADAPTER.

a. The Keithley Model 6107 pH Electrode

Adapter is designed to allow accurate and

convenient pH potential measurements with the Keithley Model 6108 Electrometer and

other Keithley electrometers having a uhf

input receptacle. The Adapter accepts a Beckman and Coleman (B-C) or a Leeds and

Northrup (L&N) connector.

The two terminals on the Model 6107 marked RRF accept a banana jack or a phone tip jack.

b. The Adapter uses Teflon insulation

on all high impedance connections.

Guard-

ed measurements can be made with the i%deL

6107 by connecting the Xl OR GND Terminal

on the Model 6L07 to the X1 OUTPUT Terminal on the rear panel of the Model 6108. The ZERO CHECK Button on the Adapter allows checking zero on the Model 610B without shorting the pH electrodes.

LGlJU 3b.

Connection Kit.

Keitniey ?lodeL bLUb Electrometer

Refer to Table 6 for com-

ponents.

c. To use the Model 6107 with the Model 6LOB, set both the ZERO CHECK Button on the NodeL 6LOB and the ZERO CHECK Button on the Model 6107 to the LOCK Position. FEEDBACK Switch on the Model 6108 can be in either the FAST or NORMAL Position.

The

d. Connect the Adapter cable directly into the Model 6lOB INPUT Receptacle.

Connect

the Xl OR GND Terminal on the Model 6107 to the Ground Post on the front panel of the

Model 6LOB if guarded measurements are not desired.

For guarded measurements connect the

XL OR GNU Terminal to the XL OUTPUT Terminal on the rear panel of the Model 6108.

a.

Insert the pH electrodes into the Model 6107 and open the ZERO CHECK Button on the

IdeL 610B.

Node1 6107

-------------

'=+ < ;Z:ro Checu

i

--(Hi

f I

I Guard

-------s-e* ---- I

0

LGURF, 37. ?lodel 6107 pH Electrode Adapter Wiring Diagram.

MODELS 61OB, 6lOBR ELECTROMETERS

NOTE

To check zero on the Model 610B, use only the ZERO CHECK Button on the Model

6107. Do not use the ZERO CHECK Button on the Model 610B.

The Button on the

Adapter isdesigned to disconnect the Hi electrode before shorting the Model

610B leads. If the Model 610B ZERO CHECK Button is used to check zero the

electrodes will be shorted and may be damaged.

f. To obtain a reading, set the Model 6108 METER Switch to CENTER ZERO.

Switch to VOLTS.

CHECK

Button on the Model 6107. Read the voltage off the lower meter scale. To convert

Use the appropriate range for the Multiplier Switch. Open the ZERO

Set the Range

the voltage to pH, consult the Handbook of Chemistry and Physics.

NOTE

If the Adapter becomes contaminated, clean it with distilled water followed by

a thorough swabbing with pure methyl alcohol, CH30H. This will suffice for most

contaminants.

5-10.

XODEL 370 RECORDER.

a. The Model 370 Recorder is uniquely compatible with the Model 6108 as well as other

Keithley electrometers,

microvoltmeters and picoammeters. The Recorder is a high quality economical instrument that maximizes the performance of the Model 6108, and many other Kefthley instruments,

even in the most critical applications. The Model 370 can be used

with the Model 6108 to record voltage, resistance, currents and charge over the Node1

6108’~ entire range.

b. The Model 6108 has the output necessary to drive the Recorder directly (1 volt, 1 milliampere), thus eliminating the need for a pre-amplifier. volts off ground.

The Recorder is specially shielded to avoid pickup of extraneous sig-

The Model 370 floats 1500

nals. The response time of the Model 370 Recorder is 0.5 second; linearity is ‘1% of full

scale.

able with front panel controls. The 6-inch chart has a rectilinear presentation.

Ten chart

speeds -

from 314 inch per hour to 12 inches per minute - are select-

The Node1 370 Recorder has a self-priming inking system. Chart paper and Fnk refills are easy to install.

c. The Model 370 is very easy to use with the Model 6108. All that is necessary is connecting the two units, setting the Model 6108 Output Switch to 1MA and adjusting an easily accessible control for full-scale recorder deflection. The furnished Model 3701 Input Cable mates wtth the output connector on the Model 610B.

MODELS 6108, 610BR ELECTROMETER

ACCESSORILY

FIGURE 38.

Especially Designed Eor use with Keithley Electrometers and Other Instruments. 370 can be directly connected to the Model 610B output with the Recorder’s accessory cable Response time and other specifications of the Model 370 Recorder are compatible with those of the Xodel 6108 Electrometer.

Maximum Recording Convenience is Obtained Using the Keithley Xodel J/U,

The XodeL

MODELS 610B, 610BR ELECTROMETERS

REPLACEABLE PARTS

SECTION 6.

6-l. ponents of the Models 610B the part description, a suggested manufacturer, the manufacturer's part number

and the Keithley Part Number.

the part. The name and address of the manufacturers listed in the "Mfg. Code"

column are contained in Table 7. 6-2.

Keithley Part Number, the circuit designation and a description of the part. All structural parts and those parts coded for Keithley manufacture (80164)

must be ordered from Keithley Instruments, Inc.

in the Replaceable Parts List, completely describe the part, its function

and its location.

Service Department, Keithley Instruments, Inc.

amp CerD Ceramic, Disc

Comp

REPLACEABLE PARTS LIST.

HOW TO ORDER PARTS. For parts orders,

a.

b.

Order

parts through your nearest Keithley distributor or the Sales

ampere

Composition

include the instrument's

The Replaceable Parts List describes the com-

and

610BR.

The last colunm indicates

REPLACEABLE PARTS

The List gives the circuit designation,

the figure picturing

model and

In ordering a part not listed

Mfg. MtF Metal Film

Mil. No. MY

serial number, the

Manufacturer Military Type Number

Mylar Dch EAl

EMC Electrolytic, metal cased p pica (10-12) ETB

f

Fig. hy

k M or meg mega (lo6

m

Deposited Carbon Electrolytic, Aluminum Electrolytic, tubular farad

Figure henry kilo (103)

or megohms ww Wirewound

milli (10e3)

TABLE 7.

Abbreviations and Symbols.

n Poly Polystyrene

Ref. Reference

u

Gar " wwvar Wirewound Variable

Ohm

micro (10s6)

volt

Variable watt

O667R

REPLACEABLE PARTS

MODELS 610B, 610BR ELECTROMETERS

MODELS 610B, 610BR REPLACEABLE PARTS LIST

(Refer to Schematic Diagram 177953 for circuit designations.)

CAPACITORS

Circuit Desig.

Cl01 Cl02 Cl03 Cl04 Cl05

Cl06 Cl07 Cl08 Cl09 Cl10

Cl11

Cl12 Cl13 c114im

c114* CL?01

c202 C203 C204 c205

Value Rating

22 pf 5 Pf

.lpf .Ol pf .OOl pf

100 pf

.OOl If 150 pf 150 pf 22 pf

W.lgf

.OOl pf

-0047 I.lf

125 pf

200 pf .OOl pf .

.OOl pf

40 I.lf 500/500 I.rf

100 uf

1000 "

200 v

1oou "

1000 V

1000 v

15 "

1000 "

200 " 35135 v 15 v-

200 " 200 "

200 "

500 " 500 " 500 "

50 v

3v

Mfg.

5Pe CerD 72982

Poly 14167 Poly 84171 Poly Poly 84171

Poly Poly Poly Poly CerD

MY CerD CerD

ETB

CerD 72982 CerD 72982 EMC 53021 EMC PA1 56289

Code Part No. Part

84171

84171 PJ

71590 CPR-1OOOJ 71590 CPR-1505 71590 CPR-15OJ

56289 SGAQ22

84411 72902 72982 81125V472P

73445

56289 TE1064

53021

Mfg.

831U2M22OK E1013-1 PJ PJ PJ

601 PE

80125VlO2P C426

80125V102P 80125V102P

505-1022-01 505-2603-01

89D217

Keithley

No.

c22-22P 25 c31-5P 26 ClOB-.lM ClOB-.OlM Cl08-.OOlM 25

C108-1OOP 25

Cl38-.OOlM Cl38-15OP C138-150P

C72-22P 22

c41-0.lI.l

C22-.OOlM C22-.0047M C3-125M

C48-200M

C22-.OOlM 20 C22-.OOlM C19-40M C20-500/500M C93-100M

Fig. Ref.

25 25

25 25 25

21 23 23 19

19

20 23 23 23

C206 C207 C208 c209

Circuit Desig.

D201 D202 0203 D204 D205

D206

D207 D208 D209

D210

* Used with Meter ME-53A

- Used with Meter ME-53

52

40 pf 40 vf

.Ol vf

500 pf

350 v 350 "

1000 "

25 v

Type

Silicon Zener Silicon Silicon Silicon

Silicon

Zener

Silicon Silicon

Zener

ETB EXB 56209 CerD 72982 EM

56289

DIODES

Mfg.

Number

lN645

lN715 12954 lN645 lN645 lN3256 02735

1~3256 lN723 12954 lN645 lN645 lN936

Code

01295 01295

01295

02735

01295 01295

04713

TVA1611 TVA1611 811ZSV103P 89D231

C23-40M C23-40M 23 C22-.OlM C94-500M

Keithley

Part No.

RF-14

DZ-22 RF-14 w-14

w-22 RF-22

DZ-17 RF-14 RF-14

DZ-5

23 23

23

Fig. Ref.

23 23 23 23 23

0667R

MOD~ELS 610B, 610BR ELECTROMETERS

Circuit

Desig.

MISCELLANEOUS PARTS

Description Code

Nfg.

REPLACEABLE TARTS

Keiehley Part No. Ref.

Fig.

DSZOL

--F201 (117~)

F201 (234~)

---

JlOl

---

5102

---

5103 5104 5105

---

L201 L202

Ml01

P201

_--

Pilot Lamp, Miniacure bayonet base (Mfg. No. 53) 08804 PL-20

Lamp Holder (Mfg. No. 203CE) Fuse, Fuse, slow blow, L/8 amp (Mfg. No. MDL) 71400 FU-20 Fuse Holder (Mfg. No. 342012)

Receptacle, uhf, INPUT, Mil No. SO-239A (Mfg. Dust Cap fbr JlOl

Plug, uhf, Mate of JLOl, Mil. No. 49190 (Mfg.

(F)

Reducing adapter, uhf, for CS-64 and CS-49,

(F)

Binding Post, Ground (Mfg. No. 33-286)' Binding Plug (Mfg. No. 29-43)

(F)

Binding Post, Xl OUTPUT (Mfg. No. DFZlRC) Binding Post, GUARD (Mfg. No. DFZlBLC) Receptacle, Microphone, OUTPUT (Mfg. No. 80-PCZF) Plug, Microphone, Mate of JlO5 (Mfg. No. 80-MCZM)

(0

Choke, 25 mhy (Mfg. No. 6302) Choke, 25 mhy (Mfg. No. 6302)

Meter

Meter (Alternate)

Cord Set, 6 feet (Mfg. No. 4638-13) Strain Relief

slow blow, l/4 amp, 3 AG (Mfg. No. 313.250)

No. 6804)

No. 83-822) Mil. No. UG-175/U (Mfg. No. 83-185)

72765 PL-18 75915 FU-17

75915 FH-3

91737 CS-64 80164 17495A

02660 cs-49 02660 ~CS-36 08811 BP-15

81073 BP-10 58474'

58474 BP-11BLU 02660 CS-32

02660 cs-33

76493 CH-7 76493 CH-7

80164 ME-53A

80164 m-53

93656 co-5 80164 cc-4

3,4

BP-1LR

20 20

20

3

SlOl

---

5102 5103

---

s104 _--

---

s105

---

(F) Furnished accessory.

3667R

Rotary Switch less components, Range

Rotary Switch with components, Range

Knob Assembly, Range Switch

Slide Switch, FEEDBACK

Push Button Switch, ZERO CHECK Knob Assembly, Zero Check

Rotary Switch less components, COARSE ZERO Rotary Switch with components, Coarse Zero Knob Assembly, Coarse Zero Switch

Knob Assembly,

Rotary Switch less camponents, MEDIUM ZERO

Rotary Switch with components, Medium Zero

Knob Assembly, Medium Zero Switch Knob Assembly, Fine Zero Control

1 MA CAL control

80164 SW-168 80164 203398

80164 17033A 80164 SW-45 80164 L80L4B

80164 14376A 80164 SW-166

80164 203288 80164 16373A

80164 L6373A 80164 SW-209

80164 203608

80164 L6993A 80164 16995A

3,4

3,4 3,4

3,5

3.4

REPLACEABLE PARTS

HODELS 6108, 6lOBR ELECTROMETERS

MISCELLANEOUS PARTS (Cont'd)

circuit

Desig. SLO6

_--

---

SLO7

---

-_-

SlOB

s201

T201

Rotary Switch less components, Multiplier Rotary Switch with components, Multiplier Knob Assembly, Multiplier Switch 80164

Rotary Switch less components, METER Rotary Switch with components, Meter 80164 Knob Assembly, Meter Switch 80164 14838A

Slide Switch, Output (Mfg. No. G-326) 79727 SW-45 Slide Switch, 117-234 v Power Transformer

circuit

Desig.

Value Rating

RlOl 10 Mn

RL02 R103 R104

10 n l%, 10 w ww 91637 RSE-10 R34-10 100 n la, 10 w ww 91637 RSE-10 R34-100

1 kn I%, l/2 w

R105 10 kn

Description

lO%,

l/2 ”

l%, l/2 "

Mfg. Keithley Code

80164 80164

Part No. Ref. SW-167

203348

17032A

80164

SW-165

179998

8Dl64 80164

SW-151 TR-70 19

RESISTORS

Mfg. Mfg. Keithley Fig.

Type

Code

camp 01121

DCb

79727 CFE-15

Part No. Part No. Ref.

EB Rl-1OM

R12-

1K

DCb 79727 CFE-15 R12-10K

Fig.

3, 4

3. 4

5

25 25 25 25 25

Rl06 Rl07 Rl08

RlO9

RllO Rlll

R112

Rl13

R114

R115

100 kQ 1 Ma 10 MO 100 MQ

109 n 1010 n

1011 n 10 MO

10 kR

2 kfl

l%, l%, l/2 " 1%, l/2 w DCb

1%) 2 w

1%

:; Cb 63060 Rx-1

lO%, l/2 w conlp 01121 l%,, l/2 " DCb 79727 CFE-15 Rl2-1OK

lO%, 5 w wwvar 71450 AW

R116

Rl17

RLl8

R119

R120

Rl21

RI22

Rl23

R124

~125

“330 n

lO%, l/2 "

Not Used

900 2 I%, l/2 " ww

10 kR 5%, 2 w WWVZIZ 12697 62JA RP42-10K

4

kl l%, l/2 w DCb 79727 CFE-15 R12-4K

301 kn l%, 1 w MtF 07716 CEC R94-301K

* Nominal value, factory set.

112 ”

DCb 79727 CFE-15 R12-100K DCb 79727 CFE-15 R12-1M

79727

CFE-15 R12-10M DCb 91637 DC-2 R14-100M Cb 63060

RX-1

R20-10q

Cb 63060 Rx-1

EB

Rl-1OM

RP34-2K

camp 01121 EB Rl-330

01686

E-30 R58-900

.

25 25 25 26 26

26 26 22 24 24

24 24 24 22

21

22 3, 4

21

54

0667R

63

MODELS 6105, 6LOBR ELECTROMETERS

RESISTORS (Conc'd)

REPL'ACEABLE PARTS

circuit

Desig. Value RI26

R127 R128 R129

R130 RL31

R132 RI33 R134 RI35

R136

R137

R138 ill39

R140

R14L R142 R143 R144 R145

3~ ki!

301 kn

LOO 0

LOO n

100 n

LOO n 100 n LOO n 100 n

100 n 100 n

qY eeen

150 !a

150 k.0

7.0 n 20 n 20 n 20 n 20 n

Rating

l%, l/2 w

0

l/., 1 w L%, l/2 " l%, L/2 w L%, L/2 "

L%, L/2 w

l%, L/2 w L%, l/2 w L%, L/2 w L%, l/2 "

L%, L/2 w l%, l/2 w l%, l/2 w 1%, l/2 w L%, L/2 "

L%, L/2 w l%, L/2 " l%, l/2 " L%, l/2 " l%, l/2 w

Mfg.

5Pe

DCb 79727 CFE-15

MtF

Deb DCb 79727 CFE-15 Rl2-LOO DCb

DCb

DCb 79727 CFE-15 DCb 79727 CFE-15

DCb 79721 CFE-L5

DCb 79727 CFE-15 Rl2-100 19

DCb 79721

Deb 79727 CFE-15 DCb 79727 CFE-15 DCb 79727 CFE-15

DCLI 79727

DCb 79727 CFE-15 RL2-20 27 DCb DCb 79727 CFE-15

Da DCb 79727

Code

07716

79727 79727 79727

79727 CFE-15

Mfg.

Part No. Part No. Ref.

CEC CFE-15

CFE-15 CFE-15

CFE-15

Keithley

RLZ-3K 27

R94-301K

R12-100 RL2-100 19 R12-LOO 19

R12-100 Rl2-100 19 R12-100 L9

RL2-LOO R12-100 a\,

,Rl2-@Q@ '6

RL2-L50K RL2-150K

R12-20 27 R12-20

RL2-20 27

Rl2-20

Fig.

21 19 19

19

77

21

27 28

R146 R147 R148 R149 R150

R151 R152

Rl53

R154 R155

R156 R157

RL58

R159

R160

R161 R162 RL63 RL64 R165

20 n 20 n 20 R 20 n 20 n

g&b

wQ.0 33 kc2 33 kn LO n

39.2 kn 91 kfl

27.3 kn

9.1 kn

2.73 kn

910 n

273 n 91 n

27.3 9

9.1 n 2 . 7 3 :>a

l%, l/2 " L%, l/2 w L%, L/2 w l%, l/2 w l%, l/2 w

l%, l/2 w LO%, L/2 "

lO%, L/2 w

lO%, l/4 w

L%, L/2 w .5%. 1 w

.5%, 1 w .5%, 1 w

.5%, 1 w . 5 % , 1 w .S%, 1 w .5%, l/4 w .5%, l/4"

DCb 79727 CFE-15 DCb 79727 Deb 79727 CFE-15

DCb 79727 CFE-15 Deb 79727 CFE-15

DCb camp camp 01121 EB Comp Deb 79727 CFE-15

MtF 07716 CEC

MtF MtF

MtF

ww 01686 T-2A w.4 01686

79727 CFE-15

01121 01121 CB

07716 07716

07716 07716 07716

CFE-15

EB

CEC R6L-27.3K CEC CEC CEC

CEC R61-273 CEC CEC

T-2A Rl23-2.73

RL2-20 R12-20 Rl2-20

R12-20 R12-20

BOG

R12-884 Rl-33K RL-33K

R76-10

R12-39.2K R6L-91K Rbl-9.LK

R61-2.73K R6L-910

R6L-91

R61-27.3 Rl23-9.1

28 28 28 28 28

27

1

21 21 30

30 30 30 30

29 29 29

29 29

0667R

55

RRFUCRABLE PARTS

MODELS 6LOB, 610BR ELECTROMETER:

RFSISTORS (Cont'd)

circuit

Desig.

R166 RL67

RL68 +qr %!a R169

RL70

RL71 RL72 R173 R174 R175

g;;

R178 R179 82.&l RHO

R181 (I.qyY. kn R182

Rla3 R184

RL85 LOO kn

Value

0.91 n 20 kl

I -Sk0

a2 n

220 R 330 0 lkl

20 ka

2m

945 yyy"

2.13 kn

1 7-m

Not Used

22 kn

Rating

.5%, l/4 w LO%, 5 w

l%, l/2 " l%, l/2 w L%,~ l/2 w

LO%, l/2 w lO%, l/2 " LO%, l/2 w

lO%, 5 w

lO%, 5 "

l%, l/2 " lO%, 5 w l%, l/2 w l%, l/2 w

0.5%, l/2 " l%, L/2 w

l%, l/2 w lO%, l/2 w

LO%, 2 w

Mfg.

5Pe

wa 01686

WWVar

DCb 79727 CFE-15

DCb DCb 79727

Camp ComP ComP

War 71450 AW

WVar 71450 AW DCb 79727 CFE-15

WWVar 71450

DCtl 79727 CFE-15 DCb 79727

MtF

DCh

DCb

Code Part No.

71450 79727

01121 01121 01121 EB

07716 79727

79727

01121

Mfg.

T-2A

AW CFE-15

CFE-15 EB

EB

AW

CFE-15

CEC

CFE-15 CFE-15

EB

HE

Keithley Part No.

R123-.91 RE'34-20K

R12-82

Rl-220 30 Rl-330 Rl-1K 29 RP34-20K 5 RF34-2K

R12-W RP34-2K R12-2K gJ,dk :'L R12-Br6It

Rbl-2.73K 20

R12-?W k.;rr:21 Rl2-=

RL-22K m-LOOK

q9?

Fig. Ref.

29

30

24 24

20

21 24

24

R186 R201

R202 R203

R204 R205

R206 R207 R208

R2.09 RzlO

R211 R212

Rz13

R214

*Nominal value, factory set.

15 n

4.7 !ul 10 n 22 R

470 kll

100 kn LO kn

10 h-2 10 0.

1.2 !a

1.4 kll 10 kn

XL.1 !ul

3.9 ko

LO%, L/2 w

lO%, 2 w LO%, l/2 " lO%, L/2 w lO%, 1 w lO%, 1 w

lO%, l/2 w 10%. l/2 " 101, l/2 w LO%, L/2 w l%, l/2 "

lO%, l/2 w

l%, l/2 w

lO%, l/2 w

L%, L/2 "

Camp

camp

camp Camp

Camp Camp

camp camp

Camp DCb

COW DCb

ComP DCb

01121

01121 01121 01121 01121 01121

01121 01121 01121 01121

79727 01121

79727

EB

ED3 Lu-4.7K

EB Rl-10

EB Rl-22 GB GB R2-100K 24

EB

EB EB CFE-15

EB CFE-15 EB CFE-15

Rl-15

24 24 24

R2-470K

Rl-1OK Rl-LOK Rl-10 24 RL-L.2K R12-1.4K

Rl-1OK

Rl2-l.lK Rl-3.9K R12-9@J

404 24

24

24 24

24

56

0667~

b?ODELS 610B, 610BR ELECTROMETERS

REPLACEABLE PARTS

TRANSISTORS

Circuit Desig.

QlOl QlOZ Q103 Q104

QLO5 Q106 Q201

Q202 Q203

Q204 Q205

Circuit

Desig.

VlOl v102

Vld3

NlJlllber Al380

Al380 AL380

A1380

2N65L 2N651 2N1381

2N1183 2N1381

2N1381 2N1381

NUObC!r

5586 5886

L2AT7

i-f.%. Code

80164

04713 04713 01295

02735 01295 01295 01295

VACUUM TUBES

Mfg.

Code Part No. 80164 w?V-5886-5P

80164 *EV-5886-5P 73445 EV-L2AT7

Keithley Fig. Part No.

+L8548A ;WkL854&j ~~~18548A

*+<18548A

TG-9 TG-9 TG-8

TG-11 TG-8

TG-8

TC- a

Keithley Fig.

Ref.

21 21 21 21

21 21 23

23 23

Ref.

22 22

23

"*Replace QLOL, 9102 and Q103, Q104 and VlOl, VlO2 as pairs.

Keithley Instruments, Inc.

I

00686

Film Capacitors, Inc. New York, N. Y.

04713 Motorola, Inc.

Semiconductor Products Division

Phoenix, Arizona

01121

Allen-Bradley Corp. Milwaukee, Wis.

07716 International Resistance Co.

Burlington Div.

01295

Texas Instxuments, Inc.

Burlington, Iowa Semi-Conductor-Components Division Dallas, Texas

08804 Lamp Metals and Components

Department G. E. Co.

01686

RCL Electronics, Inc.

Cleveland, Ohio Riverside, N. .I.

08811 G-C Electronics Co., Inc.

02660

Amphenol-Borg Electronics Corp.

Camden, N. J. Broadview, Chicago, Illinois

12697 Clarostat Mfg. Co., Inc.

02735

RCA Semiconductor and Materials

Dover, N. H. Division of Radio Corp. of America Somerville, N. J.

TABLE 8 (Sheet 1).

Code List of Suggested Manufacturers.

Supply Code for Manufacturers,

Cataloging Handbook H4-1.)

12954 Dickson Electronics Corp.

Order only from

(Based on Federal

0667R

57

REPLACEABLE PARTS

MODELS 610B, 610BR ELECTROMETJRS

$167 Efcon, Inc.

Garden City, L. I., N. Y.

3021 Sangam Electric Co.

Springfield, Ill.

6289 Sprague Electric Co.

North Adams, Mass.

8474 Superior Electric Co., The

Bristol, Corm.

3060 Victoreen Instrument Co.

Cleveland, Ohio

1400 Bussmann Mfg. Div. of

McGraw-Edison Co.

st. Lausi, MO.

1450 CTS Corp.

Elkhart, Ind.

2765 Drake Mfg. Co.

Chicago, Ill.

2982 ,Erie Technological Products, Inc.

Erie, Pa.

75915 Littelfuse, Inc.

Des Plaines, Ill.

76493 Miller, J. W. Co.

Los Angeles, Calif.

79727 Continental-Wirt Electronics Corp.

Philadelphia, Pa.

80164 Keithley Instruments, Inc.

Cleveland, Ohio

81073 Grayhill, Inc.

La Grange, Ill.

83125 General Instrument Corp.

Capacitor Division Darlington, S. C.

84171 Arco Electronics, Inc.

Great Neck, N. Y.

84411 Good-All Electric Mfg. Co.

Ogallala, Nebr.

91637 Dale Electronics, Inc.

Columbus, Nebr.

3445 Amperex Electronic Co. Division of

91737 Gremar Mfg. Co., Inc. North American Philips Co., Inc. Hicksville, N. Y.

93656 Electric Cord Co.

TABLE 8 (Sheet 2). Code List of Suggested Manufacturers.

for Manufacturers, Cataloging Handbook H4-1.)

Wakefield, Mass.

Caldwell, N. J.

(Based on Federal Supply Code

0667~

-I-

--

t

-

RlL.

4n

-

II II /I!r

-

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-

Tektronix 610B Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual