Tektronix 662 Instruction Manual

INSTRUCTION MANUAL

MODEL 662

GUARDED DC

DIFFERENTIAL VOLTMETER

.

WARRANTY

We warrant each of our products to be free from defects in material and workmanship. Our obligation under this warranty is to repair or

replace any instrument or part thereof which,

within a year after shipment, proves defective

upon examination. We will pay domestic surface freight costs.

To exercise this warranty, call your local field representative or the Cleveland factory,

DDD 216-248-0400. You will be given assist-

ance and shipping instructions.

REPAIRS AND RECALIBRATION

Keithley Instruments maintains a complete repair service and standards laboratory in Cleveland, and has an authorized field repair facility in Los Angeles and in all countries outside the

United States having Keithley field representatives.

To insure prompt repair or recalibration serv-

ice, please contact your local field representa-

tive or the plant directly before returning the

instrument.

Estimates for repairs, normal recalibrations, and calibrations traceable to the National Bu-

reau of Standa’rds are available upon request.

c

MODEL 662 DIFFERENTIAL VOLTMETER

CONTENTS

_I

section

GENERAL DESCRIPTION ........

1.

TABLE OF CONTENTS

Page

1

Section Page

5-5. Adjusting Hum Bal Control . . 19

5-6. Zener Diode Replacement . . . 19 l-1. 1-2. 1-3. 1-4. l-5.

1-6.

OPERATION . . . . . . . . . . . .

2. 2-1.

Description ........

Operating Modes .......

Applications ........

Specifications .......

Accessories .........

Equipment Shipped ......

Front Panel Controls

and Terminals. . . . . .

2-2.

Rear Controls and

Terminals . . . . . . .

2-3. 2-4. 2-5. 2-6.

Preliminary Procedures. . Operating Procedures. . .

Recorder Output . . . . .

Effects Due to Kelvin-

Varley Divider Out-

put Resistance . . . . .

2-7.

Effective Input Resis-

tance . , . . . . . . .

2-8. Thermal EMF Precau-

tions . . . . . . . . .

2-9.

APPLICATIONS . . . . . . . , . . . 11

3.

AC Effects on Measurement

1 1 1 2 3

3 . . 5 . . 5

. . 5 . . 6 . . 6 . . 8

9

. .

9

. .

. . 10

5-7. Meter Adjustment . , . . . . 19

CALIBRATION . . . . . . . . . . . . 21

6.

6-l. General . . . . . . . . . . . 21

6-2. Calibration Schedule. . . . . 22

6-3.

Kelvin-Varley Divider . . . .

Verification . . . . . . . . 22

6-4. Range Calibration . . . . . . . 23'

6-5. Reference Voltage Supply

Stability Test . . , . . . . 25

6-6. Oscillator Adjustment . . . . 27

ACCESSORIES . . , . . . . . . , . . 35

7. 7-l. Model 6601A High Voltage

Divider , . . . . . . . . . 35

7-2.

Rack Mounting . . . . . . . . 35

7-3. Placing in Rack , . . . . . . 36

8. REPLACEABLE PARTS . . . . . . . . . 37

8-l. Replaceable Parts List. . . . 37

8-2.

How to Order Parts. . . . . . 37

Model 662 Replaceable

Parts List . . . . . . . . . 38

3-l. 3-2.

Procedures for Measuring

Resistances . . . . . . . . 11

Theory of Measuring Resis-

tances . . . . . . . . . . , 11

Model 6601A Replaceable

Parts List . . . . . . . . . 44

Model 662 Schematic Diagram

185513 , . . . . . . . . . . 47

Model 6601A Schematic Diagram

CIRCUIT DESCRIPTION , . . . . . , . 13

4.

16321B . . . . . . . . . . . 49

4-l. General . , . . . . . . . . . 13

4-2. Reference Voltage Supply. . . 13 4-3. 4-4. 4-5.

SERVICING . . . . . . . . . . . . . 17

5. 5-l.

5-2. 5-3. 5-4.

Kelvin-Varley Divider . . . . 14

Null Detector . . . . . . . . 14

Guarding . . . . . . . . . . 15

General . , . . . . . , . . . 17

Servicing Schedule. . . . . . 17

Parts Replacement . . . . . . 17

Troubleshooting . . . . . . . 17

1165R

e Change Notice . . . . . . . . . . .Last

Page

* Yellow Change Notice sheet is in-

cluded only for instrument modifications affecting the Instruction

MaIlLlal.

MODEL 662 DIFFERENTIAL VOLTMETER GENERAL DESCRIPTION

SECTION 1.. GENERAL DESCRIPTION

1-1.

self-contained, guarded potentiometer.

0.01% limit of error, and below 100 millivolts within 10 microvolts. Since the limit of error includes all stability considerations, or manually restandardised for a full year. impedance at null for measurements from 0 to 500 volts.

age setting has at least 5-dial resolution.

lighted decimal points; 10 to 25-millivolt recorder output; input polarity switch; floating operation up to 500 volts off chassis ground; line frequency rejection greater than 45 db.

Also, full guarding minimizes leakage problems.

l-2. OPERATING MODES.

vacuum tube voltmeter.

500 volts with 20.01% limit of error and from 100 microvolts full

within 10

500 volts with an accuracy of r3% of full scale. It can also measure resistances from 1

megohm to 100,000 megohms within 'sS%.

(.. 13

- . APPLICATIONS.

DESCRIPTION.

a. The Keithley Model 662 Guarded dc Differential Voltmeter is an extremely precise

It measures from 100 millivolts to 500 volts with

the unit need not be periodically calibrated

The 500-volt reference supply permits infinite

Six dials assure that every volt-

Features for convenient use include:

b.

The Model 662 can be used as a potentiometer

six in-line readout dials with automatically

or

as a conventional

As a potentiometer, it measures from 100 millivolts full scale to

scale to 100 millivolts

microvolts.

As a VTVM, the Model 662 measures from 1 millivolt full scale to

a. The Model 662 meets exacting requirements in research, development and production

for accurate voltage measurements.

It

can be used with a recorder to detect source in-

stabilities down to 25 ppm over weeks of continuous measurements.

1065R

FIGURE 1.

Keithley Instruments Model 662 Guarded dc Differential Voltmeter.

1

GENERAL DESCRIPTION MODEL 662 DIFFFRRNTIAL VOLTMETER

Typical applications include calibrating power supp.lies and meters; monitoring noise,

b.

transients and drift in precise voltage sources , such as sener diodes and electro-chemical cells.

c. The null-detector output permits use with potentiometric recorders and digital volt-

meters equipped with automatic printout.

The Model 662 is useful in quality control,

product development, inspection and production.

L-4. SPECIFICATIONS.

AS

A POTENTIOMETER :

~'3

LIMIT OF ERROR:

TO.Ol% of reading or 10 microvolts, whichever is greater, after 30-minute

warm-up.

LONG-TEPX STABILITY:

Will operate within stated limit of error for one

TEMPERATURE COEFFICIENT: REPEATABILITY:

Within 0.0025%.

KAXIHUMNULL SENSITIVITY:

INPUT RESISTANCE: FLOATING OPERATION: INPUT ISOLATION:

Infinite at null, from 0 to 500 volts.

500 volts maximum off chassis ground.

Circuit ground to chassis ground: LOS ohms shunted by 0.05 microfarad.

RFSOLUTION CHART:

Input Voltage

Range, volts

year.

Does not exceed 0.001% per OC.

100 microvolts fuL1 scale with 3-microvolt resolution.

Maximum Usable Maximum Dial Resolution, millivolts

Full-Scale Null

Sensitivity,

millivolts

Meter

Resolution,

microvolts

.\,

./

50 - 500

5

- 50

0.5 - 5 0 - 0.5 0.01

AS A VACLUJM TUBE VOLTMRTER:

VOLTAGE RANGES:

NULL RANGES:

TCVM ACCURACY:

0.5 volt full scale to 500 volts in four decade ranges,

100 microvolts full scale to LOO volts in seven decade ranges.

i3% of fulb scale on all ranges,

sive of noise and drift. ZERO DRIFT: INPUT RESISTANCE::

Less than 10 microvolts per 24 hours, non-cumulative, after 30-minute warm-up.

50

megohms, 0.5 to SOO-volt ranges;

10 megohms, O.l-volt range;

1 megohm, 0.1 to lo-millivolt ranges.

2

1

0.1

0.01

1

0.1

10

3 3 3

except 5.5% on 100-microvolt range, exclu-

1065R

-l'

-‘.,

!’

\ !

MODEL 662 DIFFERENTIAL VOLTMETER

LINE FREQUENCY REJECTION: Greater than 45 db. GENERAL:

GENERAL DESCRIPTION

LINE STABILITY: Better than 5

ppm for 10% change in line voltage.

RECORDER OUTPUT:

output:

Adjustable 10 to 25

Output Resistance: Noise: Note:

POIARITY:

2 microvolts peak-to-peak referred to input up to 1 cps.

Recorder used must have fully isolated input, 1010 ohms minimum to ground.

Positive or negative, selectable by switch.

CONNECTORS: Input:

POWER:

105-125 or 210-250 volts (switch selected), 50-400 cps, 50 watts.

DIMENSIONS, WEIGHT:

300 ohms

Binding posts.

5-l/2" high x 17-l/2" wide x 13-l/2" deep; net weight, 25 pounds.

millivolts dc for full-scale meter deflection. maximum.

output: Banana jacks.

1-5. ACCESSORIES.

a. Model 6601A High Voltage Divider is a 1OO:l divider which extends the range of the

Model 662 to 5000 volts.

megohms.

The overall limit of error of the Model 662 with the Model 6601A is 20.02%.

The divider accuracy is 'rO.Ol% and its input resistance is 10

Section 7 gives operating instructions for the Divider.

Model 4000 Rack Mounting Kit,

b.

Model 662 to fit standard 19-inch racks. high x 19 inches wide x 13-l/2 inches deep.

containing two brackets and a top cover, converts the

Rack mounted,

the Model 662 is 5-l/4 inches

Section 7 has assembly instructions.

l-6.

EQUIPMENT SHIPPED.

The Model 662 Guarded dc Differential Voltmeter is factory-cali-

brated and is shipped with all components in place. All units are shipped for bench use.

Model 4000 Kit may be ordered for rack mounting; refer to Section 7 for assembly instruc-

tions. The shipping carton also contains the Instruction Manual.

1065R

GENERAL DESCRIPTION

MODEL.662 DIFFERENTIAL VOLTMETER

FIGURE 2. the Replaceable Parts List and the Schematic Diagram.

Model 662 Front Panel Controls and Terminals.

Circuit designations refer to

Newer Model 662's have a toggle

switch in place of the OVEN Pilot Light to turn on the instrument.

4

FIGURE 3. Model 662 Rear Controls and Terminals.

1165R

MODEL 662 DIFFERENTIAL VOLTMETER

SECTION 2. OPERATION

OPERATION

2-l.

FRONT PANEL CONTROLS AND TERMINALS. POLARITY Switch. The POLARITY Switch selects the input polarity by reversing the

a.

(See Figure 2.)

polarity of the internal reference voltage supply; thus, both positive and negative voltages may be measured. The Switch does not reverse meter polarity. On older models, the

Polarity Switch also turns the instrument on.

NULL Switch.

b.

The NULL Switch sets the null detector sensitivity for seven decade

ranges from 0.1 millivolt full scale to 100 volts.

Newer models have a

When the Switch is in the VTVM posi-

toggle

switch.

tion, the Model 662 operates as a conventional vacuum tube voltmeter for the four ranges of the RANGE Switch.

c. RANGE Switch.

50 and 500 volts full scale.

divider and the position of the decimal point light - which also

The RANGE Switch adjusts VTVM sensitivity in four steps:

It also determines the voltage across the Kelvin-Varley

serves

as a pilot

0.5, 5, ’

light - between the six Reference Voltage Dials.

Reference Voltage Dials.

d.

Six in-line dials at the top of the front panel set the

reference voltage when the Model 662 is used as a potentiometer.

e. METER ZERO Control. The METER ZERO Control adjusts the meter needle to zero. The Control is needed on only the 0.1 and l.O-millivolt null ranges; on the other ranges, the needle will normally be on zero without adjustment. The Control has a range of approxi-

mately 230 microvolts.

Input Terminals.

f.

The red HI Post is for connections to the high impedance terminal and the black LO Post is for connections to the low impedance terminal of the unknown voltage. A second set of binding posts marked LO and GND is provided for grounding the

LO input terminal to the chassis when desired. The LO terminals are connected together

internally.

NOTE

Older models have an OVEN Pilot Light which indicates when the oven controlling

the temperature for the zener diode in the reference voltage supply is on.

The

slight clicking sound is characteristic of the oven cycling.

2-2.

REAR CONTROLS AND TERMINALS. (See Figure 3.) Fuse. For 105-125 volt operation, the Model 662 uses a l-ampere 3 AG fuse. For

a.

210-250 volt operation, the Model 662 uses a 0.5-ampere 3 AG fuse.

Power Cord.

b.

The 3-wire power cord with the NEXA approved 3-prong plug provides a

ground connection for the cabinet. A 3:2 prong adapter is also provided.

NULL DETECTOR OUTPUT. Two terminals, marked + and -, supply a dc signal from the

C.

null detector.

/

OUTPUT ADJUST.

d.

A screwdriver control next ‘to the OUTPUT terminals adjusts the null

detector output between 10 and 25 millivolts full scale.

106SR

5

OPERATION

MODEL 662 DIFFEREXTIAL VOLTMETER

e. 117-234 Switch.

or 234~volt ac power lines. 2-3. PRELIMINARY PROCEDURES.

Check the 117-234 Switch and the Fuse'for the proper ac line voltage.

a.

power cord.

b. Set the Model 662 as follows:

BARGE Switch NULL Switch POLARITY Switch Reference Voltage Dials

The decimal light between the third and fourth Dials will light. Allow the instrument to

warm

the METER ZERO Control. 662 is such that no adjustment should be required after a 30-minute warm-up;

2-4. OPERATING PROCEDURES.

up for 30 minutes to meet the specified accuracy on all ranges.

With the input terminals open,

c.

The screwdriver-operated slide switch sets the blodel 662 for 117

Connect the

500 VTVM + Zero

set the NULL Switch to 0.1 MV and zero the meter with

Then return the NLTLL Switch to VTVM. The stability of the Model

-3

a. The Model 662 is used first ,as a VTVM to determine the approximate value of the

unknown voltage,

20.01%.

It is then used in the potentiometric mode to determine the voltage to

[7] 000000

E” 0000

Potential -

A

FIGURE 4. measuring at ground and for floating.

In A, the unknown voltage has one terminal at ground.

the LO and GND Posts of the Model 662.

In B, the unknown voltage has both terminals off ground potential. Note this floating

or off-ground potential must be Less than 500 volts.

used.

Input Connections to Hodel 662.

The two diagrams show the input circuit for

Also note the shorting link is n&

B

The shorting link is between

.-*

6

0665

MODEL 662 DIFFERENTIAL VOLTMETER

OPERATION

Cl

NOTE

The Model 6601A High Voltage Divider extends the Model 662 range to 5000 volts. Refer to Section 7 for operating instructions.

VTVM Operating Procedures.

b.

Eleven full-scale ranges are available for VTVM operation.

1.

is at VTVM, the RANGE Switch determines one of four full-scale ranges. By putting the

six Reference Voltage Dials at Zero, the Model 662 can then operate as a VTVM on the seven null ranges.

Connect the unknown voltage to the input terminals,

2.

impedance terminal of the unknown. Refer to Figure 4.

Switch the RANGE Switch to the most sensitive range for an on-scale meter deflec-

3.

tion.

c. Potentiometric Operating Procedures.

NOTE

Avoid large overload voltages on the null detector. No permanent damage will occur even with 500-volt overloads, but some open circuit offset will be caused in the null detector. capacitors,

will disappear after about five minutes.

The offset, due to the polarization of the input filter

using the LO Post for the low

When the NULL Switch

Leave the RANGE Switch at the last setting used in the VTVM operation. If the

1.

VTVM reading is negative,

Set the first two.Reference Voltage Dials to the first two digits of the unknown

2.

voltage found in the VTVM operation.

Set the NULL Switch to the initial

3.

null setting shown in Table 1, Adjust

the Voltage Reference Dials progressively for zero meter deflection while increasing the null detector's sensitivity with the

NULL Switch.

indicate the voltage being measured is more positive than the Reference Voltage Dial setting.

The most accurate resistors in the Kelvin-Varley divider are in the first two Reference Voltage Dials. Therefore,

the first two dials as much as possible.

The value of the unknown voltage is read directly from the Reference Voltage Dials.

4.

Deflections to the right

reverse

the POLARITY Switch position.

RANGE Initial Most Sensitiv Switch Setting

500 v 100 v

50 v 10 v

5v 1v

0.5 v 100 MV

TABLE 1. and Settings.

NOTE

to obtain the most accurate readings, use

NULL Switch NDLL Switch

Setting Setting

Recommended Null Sensitivities

10 MV

1.0 Mv

0.1 MV

1065R

a) The Dial reading will be within the specified limit of error if the NDLL Switch

7

OPERATION MODEL 662 DIFFERENTIAL VOLTMETER

is at the most sensitive setting (Table 1) for the range used and if the meter indicates as close to null as possible.

Null does not have to be reached.

b) Readings can be made from only five Reference.Voltage Dials to be within spec-

ifications (20.01% of reading or 10 microvolts).

Using the sixth Dial allows the

instrument to approach null closer, further reducing loading effects upon the source.

2-5. REcoBsm OUTPUT.

a. Recommended recorders for use with the Model 662 are the F. L. Moseley Autograf 680 series recorder and the Minneapolis Honeywell recorder (LOmv-0-1Omv scale, 50 kilohms input resistance). Any recorder used

input must be fully isolated (1.010

Before attaching the recorder , set all Reference Voltage Dials to zero. Disconnect

b.

must

be able to float 500 volts off ground and its

ohm minimum leakage resistance to ground).

the unknown voltage and short both Model 662 input terminals. Set the NULL Switch to 10 MV. Connect the recorder to the OUTPUT terminals on the Model 662 rear panel.

Set the Reference Voltage Dials to LO millivolts to apply an accurate LO-millivolt

c. potential to the null detector on the lo-millivolt null range. This will provide a fullscale recorder output which can be matched to the recorder’s range between 10 and 25 milli-

volts by adjusting the OUTPUT ADJUST Control.

To obtain accurate results and/or to prevent damage to the instruments, the recorder

d.

must be able to float off-ground with the Model 662. Leakage and pickup between the two instruments should also be minimized.

wake sure neither recorder terminal

1.

is grounded. Use a 3-wire grounded power

line for the recorder. If a 2-wire line is used, connect the recorder chassis and the Model 662 chassis with a separate lead.

Model

1 Red

662

Minimize all sources of leakage be-

2.

DEigj =zf + ;:j:::

tween the output terminals, the recorder and ground. Use polystyrene or Tefloninsulated wire where possible. If the connecting wires are shielded, connect

the shield to the LO Post.

Avoid long leads between the Hodel

3.

662 and the recorder.

.

FIGURE 5. Recorder Filter. A filter be-

1 Black

tween the Model 662 and the recorder may

4.

ground

ings ,

If difficulty is encountered in off-

measurements,

such as unsW7le read-

connect a lo-microfarad ca:?scitor

be necessary when using the O.l-millivolt null detector range,

between the LO and GND terminals .rn the Model 662 front panel.

.

j

/

NOTE

Do not short either Node1 662 ,.,‘:tput terminal to the case; this may damage the

Kelvin-Varley divider.

../

0665

:

MODEL 662 DIFFERENTIAL VOLTMETER

OPERATION

i-:: e.

filter between the Model 662 and the recorder.

Note the filter

2-6. EFFECTS DUE TO KELVIN-VARLEY OUTPUT RESISTANCE.

a. When the Model 662 is used for nulling on the O.l-millivolt range, the last Reference Voltage Dial may appear to be inaccurate. drop across the Kelvin-VarLey divider, This effect involves only the null detector sensitivity and not the accuracy of the Dial setting. When the Model 662 is as near to null as possible, the Reference Voltage Dial setting is correct within the instrument's specified limit of error. There is no effect present at null.

b. The effect is most apparent on the 0.1,

on the O.l-millivolt range a O.l-millivolt off-null setting of the reference voltage will

not produce a full-scale meter deflection. This is because the Kelvin-Varley divider output resistance is significant compared to the shunt resistance across the null detector

meter. The IR drop across the divider will cause the meter to be off up to 6%, depending

upon the Reference Voltage Dial settings. On the lOO-millivolt range the maximum error

is 1%.

c. The amount of deflection on the meter is equal to the ratio

If there is substantial recorder jitter on the O.l-millivolt null range, place a

Refer to Figure 5 for this connection.

must

also be insulated from ground,

The apparent error is due to a voltage

1 and lo-millivolt null ranges. For example,

The effect cannot be observed on the other null ranges of the Model 662.

R*

%-I

+

NW

5

where R,, is the shunt resistance across the meter (50 megohms for the 100 to l-volt null

ranges, 10 megohms for the lOO-millivolt range,

and 1 megohm for the 10 to~O.l.-

millivolt ranges);

Rkv

is the output resistance of the Kelvin-Varley divider, which is a maximum of

62.4 kilohms at Reference Voltage Dial settings of 2 4 5 4 5 5 and 2 5 4 5 5 5 and a minimum of 100 ohms at settings of 4 9 9 9 9 8 and 0 0 0 0 0 2.

NOTE

'For a fuller treatment of the effect source resistance has on measurements,

send for the Keithley Instruments Product Note, "The Effective Input Resis-

tance of Potentiometric Voltmeters."

2-7.

EFFECTIVE INPUT RESISTANCE.

The input resistance of the voltmeter for the seven null ranges varies from 50 to

a.

1 megohm as given in Table 2. This, however, is not the Model 662's effective input resistance. Its input resistance is considerably higher due to the potentiometric principle of operation. When the reference voltage (Reference Voltage Dial setting) is much greater than the meter reading, the value is:

Fin"

&I %

V

Equation 1

where R.

Eh*is the setting of the Reference Voltage Dials in volts; Rn is the shunt or input resistance of the null detector meter in ohms; V is the null detector meter reading in volts.

1065R

is the effective input resistance of the Model 662;

9

UPERATION

To find the loading effect the Model 662 will have on a circuit, use equation 1 to

b.

compute the effective input resistance. finite.

Off null, the input resistance is usually high compared to the.internal resis-

At null, where V=O, the input resistance is in-

MODEL 662 DIFFERENTIAL VOLTMETER

tance of the unknown voltage, and loading will not be enough to affect the measurement accuracy.

The graph in Figure 6 shows the Model 662 effective input resistance for the

three most sensitive null ranges as a percent of meter reading off null (V/Ed).

'2

2-a.

THRlWAL KMF PRECAUTIONS.

thermal emf

errors

for measurements using the most sensitive null ranges. Since the

Observe standard thermocouple techniques to reduce

Model 662 can read to 3 microvolts, thermal emf's can introduce considerable errors into

the measurements. In general, use pure copper leads throughout the system when measuring fn the microvolt rsnge. For extensive measurements in the microvolt region, request the

article, DC Microvolt Measurements, from'Keithley Instruments, Inc., or its representative.

2-9.

unknown voltage,

AC EFFECTS ON i%ASDREMENTS. To minimize errors from ac signals present in the

the Model 662 employs a chopper-stabilized null detector operating at a 42-cps chopping rate with a 3-section R-C filter at the input. Very large ac components on the measuring lines, however, may reduce off-null sensitivity. Also, heavy 60-cps pickup will be observed as needle quiver.

If ac components affect measurements by the

Model 662, additional filtering is required. For a single-frequency ac signal, a twin-

T filter is effective.

For a variable frequency signal,

use an ordinary low-pass filter.

Voltage Input Range

Resistance

,

'

300 volts 50 megohms

50 volts 50 megohms

5 volts 50 megohms

0.5 volts 50 megohms

Input Null Range

100 volts

10 volts

1 volt

100 millivolts

10 millivolts

1 millivolt

0.1 millivolt

TABLE 2.

by Ranges.

Model 662 VTVM Input Resistance

Resistance for Null Ranges is

Resistance

( Skwing)

50 megohms

10 megohms

1 megohm 1 megohm 1 megohm

when the Reference Voltage Dials are set

to zero.

FIGURE 6.

Model 662 Off-Null Effective Input Resistance. The graph shows the effective input resistance for the 0.1 to lo-

millivolt ranges.

Percent off null is V/Ed "

as defined in Equation 1.

IO

1265R

MODEL 662 DIFFERENTIAL VOLTMETER

APPLICATIONS

The Model 662 can be used to rapidly measure

3-l.

SECTION 3.

PROCEDURRS FOR MEASURING RRSISTANCES. resistances from 1 megohm to 100,000 megohms with an accuracy of 25%. To measure resistance, isolated lead to the RI terminal to prevent measuring leakage between the leads. RANGE Switch to 500.

a.

adjust the Reference Voltage Dials to obtain a full-scale meter deflection.

connect the unknown resistor across the Model 662 RI and LO terminals. Use a short

Set the

Then determine the value of the resistor as follows:

For resistances between 1 megohm and 1000 megohms,

set the NULL Switch to 10 volts;

Subtract

10.000 from the Dial setting and multiply the difference by 5 to obtain the value of the

resistor in megohms.

b.

volt;

For resistances between 1000 megohms and 10,000 megohms,

adjust the Reference Voltage Dials to obtain a full-scale meter deflection.

set the NULL Switch to 1

sub- '

tract 1.0000 from the dial setting and multiply the difference by 50 to obtain the value

of the resistor in megohms.

For resistances between 10,000 megohms and 100,000 megohms, set the NULL Switch to

c.

1 volt; adjust the Reference Voltage Dials to obtain a convenient deflection on the meter.

Calculate the value of the resistor using,

Rx = 50 Ed megohms

v

Where Rx is the unknown resistance;

Ed is the Reference Voltage Dial setting in volts;

V is the meter reading in volts. 3-2.

THEORY OF MEASURING RESISTANCES. The above method for determining the value of an unknown resistor is based upon the equation

for the circuit.

(See Figure 7;) If an unknown resistance is across the Model 662 input terminals, then

Ed = i (Rx + Rn)

Equation 3

Where Ed is the Reference Voltage Dial set-

ting in volts;

i is the current in the circuit;

Rx is the unknown resistance;

Rn is the input resistance of the null

detector meter in ohms.

The current can be written i = V/R,,, where

V

is the null detector meter reading in

volts.

Equation 3 now becomes

Equation 4

Equation 2

Ed

I

FIGURE 7.

Simplified Model 662 Circuit for Measuring Resistances. Rr is the unknown resistance. Rn is the input resistance of

the null detector; V is the null detector; Ed is the buckout voltage.

1065R

11

APPLICATIONS

MODEL 662 DIFFERENTIAL VOLTMETER

If measurements are made on the 1 to LOO-volt null ranges, the input resistance, Rn, is

50 megohms.

Equation 4 becomes

Rx"5x107

Equation 5

This is the basis for the simplified calculations in paragraph 3-1.

.'-J

~2

7

12

1065R

MODEL 662 DIFFERENTIAL VOLTMETER

.-.

SECTION 4.

CIRCUIT DESCRIPTION

4-l.

GENERAL.

The Model 662 Differential Voltmeter measures voltage by the potentiometric (null) method. The variable known voltage is an ultra-stable 500-volt reference supply used in conjunction with a precision multi-dial Kelvin-Varley divider. Electronic referencing of the 500-volt output to a zener diode standard maintains the reference supply's stability and accuracy.

This method eliminates repeated manual standardization. The difference between the divider output and the unknown voltage is indicated by the null detector, a chopper-stabilized vacuum-tube voltmeter. At null the unknown voltage can be read directly from the in-line dials of the Kelvin-Varley divider.

The input and null

detector are fully guarded to avoid leakage.

NOTE

Refer to Schematic Diagram 185513 for circuit designations,

INPUT

TERMINALS

GUARDED

NULL

DETECTOR

B-DIAL

KELYIN-“ARLEY

0l”lOER

REFERENCE

VOLTAGE

SUPPLY

Simplified Model 662 Circuit Diagram.

4-2.

FIGURE 8.

REFERENCE VOLTAGE SUPPLY.

a. Unregulated voltage from transformer T3001 is rectified by a silicon half-wave rec-

tifier, D3001, and is filtered by capacitors C3001 and C3002.

The voltage then is applied

to the regulator series pass tube, V3004. Regulator tube V3005 is used to keep the screen

of V3004 at a constant potential.

b. To obtain a stable, accurate voltage, the 500-volt output of V3004 is sampled by a divider network of wirewound resistors, R3023 to R3028. The divider network ratio is adjusted with potentiometer R3025 to better than 0.01%.

) sample voltage from the divider network to the voltage across zener diode D3003.

Light modulator E3002 compares the

Any dif-

ference between the two voltages is chopped by E3002 and amplified by a two-stage ac-coupled

amplifier, V3001. The amplified output of V3001 is converted to a dc signal by light mod-

1065R

13

CIRCUIT DESCRIPTION

MODEL 662 DIFFERENTIAL VOLTMETEX

ulator E3001 and then is amplified by the two-stage differential dc amplifier, V3002 and v3003.

input variations.

c. An ultra-stable aener diode, D3003,is used as the basic reference; typical variations are limited to less than 10 ppm/OC. Thus, a highly stable reference which eliminates manual standardization is provided with respect to both time and temperature. The zener diode will also withstand shock and vibration.

d.

ley divider or Ft is dfvided to 50, 5 or 0.5 volts by very stable wirewound resistor’net-

works.

der consists of resistors R3030, R3032 and R3033; the S-volt, of R3030, R3035 and F.3036; and the 0.5-volt of R3030, R3038 and R3039. Using potentiometers R3032, R3035 and B3038 accurately sets the voltage division on each range.

4-3.

a. The Kelvin-Varley divider precisely divides the reference voltage for nulling an

unknown voltage. It is, in effect, a constant input impedance decade potentiometer, con-

sisting of resistors R3040 through R3099. The resistors within each decade are matched; the decades are matched for each instrument.

b.

parallels two resistors of the preceeding string. Reference Voltage Switch, S3003, the total resistance is 40 kilohms (80 kilohms in parallel with the 80 kilohms total resistance of the four remaining strings). With the RANGE Switch set at 500, 100 volts dc will appear across the contacts of Reference Voltage

Switches S3004, 10 volts across S3005, 1 volt across S3006, 0.1 volt across S3007 and 0.01

volt across S3008.

The amplifier output is applied to the grid of the series tube, V3004, to nullify

Capacitor C3004 is used in the ac feedback circuit.

The regulated 500-volt output of V3004 is either applied directly to the Kelvin-Var-

The’XANGE Switch, S3010, determines which network is used. The 50-volt range divl-

KELVIN-VART.EY DIVIDER.

Each decade of the Kelvin-Varley divider, except the first, R3040 through R3045,

Between the two contacts of the first

1>

y>,

2’

4-4. NULL DETECTOR.

back amplifier.

stage R-C filter. The signal is then amplified and applied to the meter.

a. The null detector has three full-scale sensitivities, O.l;l and 10 millivolts.

Above the LO-millivolt range, the input is divided by resistors R1004 through R1009 to

the 10 millivolts. back resistors, RLO4C to R1042, in the circuit. A three-stage R-C filter, consisting of Rl.010, RlOll, C1003, RL012, Cl004, RlOl8 and C1005, decreases the ac input components.

The light modulators ElOOl’and El002 convert the difference between the filtered

b. input voltage and the output of the Kelvin-Varley divider into an ac voltage, which is fed to a four-stage ac coupled amplifier, VlOOl and VlOO2. demodulated by light modulator El003 and filtered by capacitor C1019. The null detector

meter, MlOOl, indicates the value of the filtered signal.

light modulators. frequency minimizes 60-cps pickup effects.

One arm of the feedback network is formed by resistors R1043 to R1046, and one of

c.

the feedback range resistors, R104C to R1042. The feedback is applied to light modulator E1002.

A zero-control network is used to buck out thermal emf’s at the input on the two

d.

The input signal is attenuated, if necessary, and sent through a three-

The Model 662 uses a null detector with a chopper stabilized, feed-

The full-scale sensitivities are determined by one of three feed-

The amplifier output is then

A 42-cps oscillator drives the

Using a drive source harmonically unrelated to the standard line

Resistor R1039 forms the second shunt arm.

14

1065R

MODEL 662 DIFFERENTIAL VOLTMETER

CIRCUIT DESCRIPTION

most sensitive ranges. resistors R1013 thrnugh R1016.

mately

e.

a 60-microvolt span.

The null detector output is obtained acrcss resistors R1045 and R1046, which are

The network consists of a 1.34~volt mercury battery, BTlOOl, and

The zerc control on the front panel, R1016, has approxi-

in the feedback network. Potentiometer R1045 adjusts the output from 10 to 25 millivolts at full scale.

The output voltage is proportional to the full-scale meter reading.

4-5. GUARDING. Guarding is accomplished by floating the null detector and the input circuitry at a voltage equal to the input voltage from a low impedance source. guarding eliminates leakage between the input terminal and ground.

Such leakage in an

This full

unguarded circuit is difficult to avoid, even under laboratory conditions, and can result

in sizeable errors. of 108 ohms will introduce 1% error.

For example, in an unguarded circuit with a l-megohm source, leakage

A guarded circuit eliminates this element of error.

1065R

15

MODEL 662 DIFFERENTIAL VOLTMETER

SERVICING

SECTION 5.

5-1. GENERAL.

Model 662.

stability of the instrument. 5-2. SERVICING SCHEDULE.

care required of high-quality electronic equipment. der ordinary use except a pilot lamp, fuse or, occasionally, a vacuum tube.

5-3.

Model 662. which meet the specifications.

only as an assembly. tors R3040 to R3099. Resistors R3023, R3024 and R3026 and resistors R3033, R3036 and R3039 are also parts of assemblies. Reorder using the Keithley part number (see Section

8) and replace all resistors in the assembly. power supply stability, its representative.

PARTS REPLACEMENT, The Replaceable Parts List in Section 8 describes the electrical components in the

a.

Replace resistors within any one of the first three Kelvin-Varley divider decades

b.

Section 5 contains the maintenance and troubleshooting procedures for the

Follow these procedures as closely as possible to maintain the accuracy and

The Model 662 needs no periodic maintenance beyond the normal

Replace components only as necessary, and use only reliable replacements

Refer to the Replaceable Parts List for the part number for resis-

order sener diode D3003 only from Keithley Instruments, Inc., or

Refer to paragraph 5-6 for instructions to replace the zener.

SERVICING

No part should need replacement un-

Because of its importance in maintaining the

5-4. TROUBLESHOOTING.

The following procedures are for repairing troubles which might occur in the Model

66;:

Table 3 lists equipment recommended for troubleshooting.

ly located or repaired,

the troubleshooting, check the vacuum tubes.

difficulty. All tubes can be readily tested on a grid-modulated tube tester. If repla-

cing a tube does not correct the trouble, continue the procedures. Replacing tubes does not necessitate recalibration of the instrument.

ted in the Table do not clear up the trouble, the difficulty will have to be found through

Tektronix Type 503 Oscilloscope

megohm input resistance, 1 volt to 500 volts

Use these procedures to troubleshoot and use only specified replacement parts.

If the trouble cannot be readi-

contact Keithley Instruments, Inc.,or its representative.

b. Paragraph 7-2 describes how to remove the Model 662 cover.

Normally, replacing tubes will clear up the

Table 4 contains the more common troubles which might occur. If the repairs indica-

C.

Instrument Use

Check wave forms

dc voltmeter, 10% accuracy, minimum lOO-

Grid-modulated tube tester

Circuit checking

Test vacuum tubes

Before proceeding with

TABLE 3.

their equivalents.

1065R 17

Equipment Recommended for Model 662 Troubleshooting. Use these instruments or

SERVICING

teference voltage supply lrifts after 30-minute ram-up, requiring freLuent adjusting of the :ange controls, R3025, L3032, R303.5, R3038

MODEL 662 DIFFERENTIAL VOLTMETER

One of the divider resis-

Return the instrument for

tom, R3023 to R3028, is factory check-out

value rapidly dur-

easurements ou

:olerance on all ranges

;pecifications on one :ange other than 500rolt range

easurements are out 0 specifications on all :anges other than SOOrolt range

R3023 to R3028 is fault

divider network is

Return the instrument for

the resistors used for each

Try to bring the

ranges within specifications

by calibrating with the pot-

entiometers in the network. See paragraph 6-4.

If this

does not work, check indivi-

ty resistor

18

TABLE 4 (Sheet 1). Model 662 Troubleshooting.

MODEL 662 DIFFERENTIAL VOLTMETER SERVICING

,,-

Difficulty Probable Cause

Measurements are out of One of the Kelvin-Varley

specifications on any

divider resistors is faulty

See paragraph 6-3

Solution

range when the Reference Voltage Dials are at any setting other than 49 99 9 10

Instrument is out of

specifications on all

Resistor R1003 is faulty Check resistor; replace if

faulty null ranges above 10 millivolts

TABLE 4 (Sheet 2).

Model 662 Troubleshooting.

a point-by-point check of the circuits. Refer to the circuit description in Section 4 to

find the more crucial components and to determine their function in the circuit. The complete circuit schematic, 185513, is found in Section 8.

5-5.

ADJUSTING RUM BAL CONTROL.

a. Potentiometer ~1048 (Figure 20) min-

imizes 60-cps pickup in the null detector.

Misadjustment will reduce sensitivity and

cause needle quiver.

To adjust the potentiometer, set the

b. Reference Voltage Dials to zero and short the input terminals. Attach an oscillo-

scope to the junction of capacitor Cl016 and resistor R1035 (from pin 6 of V1002). Figure 9 shows the wave form if potentio-

meter R1048 is adjusted for minimum output.

5-6.

ZONER DIODE REPLACXMENT. Zener diode, D3003, is a reference for the voltage divider, FIGURE 9. Wave Form with R1048 Adjusted. resistors R3023 to R3028.

The values of re-

A Type 503 Oscilloscope was used; horison-

sistors R.3027 2nd R3028 (Figure 22) are de- tal sweep was 20 msec/cm; vertical, 10

termined by the reference voltage across di-

V/Cm.

ode D3003. When the zener is replaced, the

value of these two resistors may have to be

changed. 5-7.

METER .AD.TUSTMERT.

a. Potentiometer R1043 (Figure 20) is the internal meter sensitivity adjustment. It

sets the cLrrent through the meter to indicate

a full-scale deflection for a full-scale

applied voLtage.

Warm -:i i-he Model 662 fcr 30 minutes.

/

b.

range and se;: the I. ~L'erence Voltage Dials

Set the NULL Switch on

to

.OOOlOO.

Adjust potentiometer R1043 until

the

O.l-millivolt

the meter re'~is fui~ si~sle.

1065~

19

CALIBRATION

MODEL 662 DIFFERENTIAL VOLTMETER

FIGURE 10. Keithley instruments are also shown.

20

Models 662 and 66OlA Traceable Chart to National Bureau of Standards. Other

MODEL 662 DIFFERFXCIAL VOLTMETER CALIBRATION

SECTION 6.

6-l. GENERAL.

a. The following procedures are recommended for calibrating the Model 662. Use the equipment recommended in Table 5. ibrating an -fO.Ol% instrument -'are not available or if difficulty is encountered, contact Keithley Instruments or its,representative to arrange for' factory calibration.

Four procedures are covered:

b. calibration, reference voltage supply stability test and oscillator adjustment.

C. If the Model 662 is,not within specifications after the calibration, follow the troubleshooting procedures or contact Keithley Instruments, Inc., or its representative.

Instrument use

Electra Scientific Industries Model SV194B Voltage Calibrator, corrections on certificate

Electra Scientific Industries Model RV722 Decade Voltage Divider; terminal linearity, ?-1 ppm; certificate corrected to CO.2 ppm

&0.005% accuracy with

If proper facilities - especially important for cal-

Kelvin-Varley divider verification, voltage range

CALIBRATION

Range voltage calibration

Voltage divider for range calibration

Electra Scientific Industries Model LC875B Lead Compensator

Hewlett-Packard Model 200CD Oscillator

Keithley Instruments Model 150A Microvoltmeter

Keithley Instruments Model 241 Regulated High Voltage Supply

Keithley Instruments Model 662 Guarded dc Differential Voltmeter

Mosley Instruments. Model 680 Direct Reading Recorder

Tektronix Type 503 Oscilloscope Weston Instruments Model 3 Type 7 Saturated

Standard Cell

Weston Instruments Model 66 Oil Bath

Range voltage calibration

Monitor oscillator frequency

Null detector for range calibration

Voltage supply for range calibration

Check voltages in Kelvin-Varley divider

Recorder for reference voltage supply sta bility

Check wave forms Range calibration and reference voltage

supply stability

Range calibration and reference voltage

supply stability

TABLE 5.

equivalents.

1065R 21

Equipment Recommended for Model 662 Calibration.

Use these instruments or their

CALIBP.ATION

MODEL 662 DIFFERENTIAL VOLTMETER

Control

Meter Calibrate

Hum Balance Oscillator

500-volt Calibrate SO-volt Calibrate 5-volt Calibrate

0.5-volt Calibrate

circuit

Desig. R1043

R1048 R200 7

R3025 R3032 x3035 R3038 22

Fig. Ref.

20 20 22

22 22 22

Refer to Paragraph

5-7 S-5

6-6 6-4

6-4 6-4 6-4

TABLE 6. Model 662 Internal Controls. The Table lists all internal controls, the fig-

ure picturing the location and the paragraph describing the adjustment.

6-2.

calibration (paragraph 6-4).

or if components in the divider have been replaced.

CALIBRATION SCHEDULE.

a. Recalibrate the Model 662 yearly.

This normally means performing the voltage range

The other verifications need not be done.

Verify the Kelvin-Varley divider (paragraph 6-3) only if trouble is suspected in it,

b.

Also make the voltage range calibra-

tion after verifying the divider accuracy.

,’

c. Check the reference voltage supply stability (paragraph 6-5) only if trouble is

suspected in the supply or if some of its components have been replaced. 6-3.

KELVIN-VARLEY DIVIDER VERIFICATION.

a. There is no in-field calibration for the Kelvin-Varley divider: its accuracy can only be verified. The divider accuracy depends upon matching resistors and switches. At manufacture, S3004, is matched to rO.O0125%. accuracy of better than 0.0025%.

each resistor within the first two Reference Voltage switches, S3003 and

The resistors in the switches are checked as a set to an

Individual resistors cannot be replaced without remat-

ching the string at Keithley Instruments.

Kelvin-Varley Divlder~ Accuracy Verification Procedures.

b.

Use another Model 662 Differential Voltmeter or equipment with better limit of

1.

error to match the Model 662 under test.

instrument under test to the RI terminal of the Model 662.

Connect the wiper arm of Switch S3008 of the

Connect both LO terminals.

NOTE

Be careful of high voltages when working within the Model 662.

up to 900 volts

dc is present at various points.,

Set

2.

the dials to random settings on both instruments.

Settings should match to

20.01%. This procedure, however, only indicates the Kelvin-Varley divider accuracy,

The errors of the two instruments may be additive,

causing a false verification. The

most accurate way is to use standard procedures for checking a Kelvin-Varley divider

or to return the Model 662 to Keithley Instruments, Inc., for checking.

J

22

1065R

MODEL 662 DIFFERENTIAL VOLTMETER CALIBRATION

If any resistor fails to test out, the entire divider string will have to be re-

3.

matched at the factory.

6-4.

RANGE CALIBRATION.

a. The reference voltage supply has a 500-volt output which can be attenuated to SO, 5 or 0.5 volts. accurate buckout voltage.

This voltage is then divided by the Kelvin-Varley divider to provide the

Each of.the four voltage ranges is set by internally adjusting

potentiometers R3025, R3032, R3035 and R3038 (Figure 22).

The ranges are calibrated by applying an accurate voltage to the Model 662 for each

b. setting of the RANGE Switch. The Model 662 is set to furnish the equivalent buckout voltage, and the internal range potentiometer is adjusted until the voltmeter indicates a null.

NOTE

The accuracy of the Model 662 calibration will be no greater than the accuracy of the voltage source used for calibrating.

Unless the user is

familiar with techniques for obtaining accuracy greater than 0.002%

(20 ppm), it is better to return the Model 662 to the factory for range

calibration.

c. The most critical part in range calibration is establishing a reference source

whose accuracy exceeds 0.002%. Use the Model SV194B Voltage Calibrator for the 500, 50

5 and 0.5-volt outputs.

Establish the accuracy of these outputs by determining the cor-

Model LC 875B

Model RV722

FIGURE 11. Block Diagram to EsL&i.sh System Accuracy for Model 662 Range Calibration.

Fully guard the entire system to ‘freer .: leakage errors.

Use a 1-kilohm copper resistor

to shunt the null detector. Set ‘Table 3 :.jr recommended equipment.

1065R

23

CALIBRATION MODEL 662 DIFFERENTIAL VOLTMETER

rections for the calibrator’s CALIBRATION and OUTPUT dials at these outputs. accuracy can be’determined to approximately 10 ppm.

Added to the accuracy of the standard

The system’s

cell, total accuracy should be approximately 12 ppm. Note that this depends upon properly executed procedures.

Procedures to Establish System Accuracy.

d.

Set up the system shown in Figure 11.

1.

Use the 9.9~megohm extender for only the

0.5 and 5-volt outputs. Establish the corrections for the CALIBRATION dial setting for Model SVl94B out-

2.

puts of 500, 50, 5 and 0.5 volts.

Set the Model 241 Voltage Supply to 500 volts.

Set

the Model RV772 Divider to a voltage equal to that of the standard cell. Adjust the

Model SVL94B ratio dial until the null detector indicates a null. The difference be-

tween the settings of the Model RV772 Divider and the ratio dial is the Node1 SVL94B

correction factor at 500 volts. With this correction,

the 500 volts may be set to

within approximately 12 ppm.

Connect the null detector to the 50,

3.

5 and 0.5-volt taps of the Model SV194B Cal-

ibrator in that order. Set the Model F&V722 Divider to corresponding voltages. Use the

9.9-megohm extender for the 5 and 0.5-volt outputs.

(See Figure 11.) The difference read on the null detector is the correction factor for each of the three voltages. These voltages may also be set to within 12 ppm.

Use the four correction factors for calibrating the Model 662 range setting.

4. Procedures for Range Calibration.

e.

Set up the system shown in Figure 12.

1.

10 ppm.

Use the dial correction factors found for each output.

was properly determined,

500-volt Range Calibration: Set the Model 662 controls as fo.llows:

2. RANGE Switch

Reference Voltage Dials

the input voltage to the Model 662 should be correct to 20 ppm.

500 4 9 9.9 9 10

The standard cell should be certified to

If the system accuracy

NULL Switch VTVM POLARITY Switch

+

Adjust the Voltage Calibrator to apply 500 volts to the Model 662. Turn the Model 662 NULL Switch to 10 MV and adjust the 500 V CAL potentiometer, R3025 (Figure 22), for null on the Differential Voltmeter.

50-volt Range Calibration:

3.

Set the Model 662 controls as follows:

RANGE Switch 50 Reference

Voltage Dials

NULL Switch POLARITY

4 9.9 9 9 LO

LO M-v

*

j>#

Adjust the Voltage Calibrator to apply 50 volts dc to the Model 662. Adjust the 50 V

CAL potentiometer, R3032 (Figure 22), for an off-null reading on the Model 662 equal to

the correction factor at 50 volts.

MODEL 662 DIFFERENTIAL VOLTMETER

CALIBRATION

FIGURE 12.

Block Diagram for Model 662 Range Calibration.

to prevent leakage errors.

5-volt Range Calibration:

4.

See Table 5 for recommended equipment.

Set the Model 662 controls as follows:

Fully guard the entire system

RANGE Switch 5 Reference Voltage Dials

4.9 9 9 9 10 NULL Switch 1MV POLARITY Switch +

Adjust the Voltage Calibrator to apply 5 volts dc to the Model 662. Adjust the 5 V

CAL potentiometer, R3035 (Figure 22), for an off-null reading on the Model 662 equal to the correction factor at 5 volts.

0.5-volt Range Calibration: Set the Model 662 controls as follows:

5. RANGE

0.5

Reference Voltage Dials .4 9 9 9 9 10

NULL Switch

POLARITY

0.1 MV +

Adjust the Voltage Calibrator to apply 0.5 volt dc to the Model 662. Adjust the 0.5 V

CAL potentiometer, R3038 (Figure 22), for an off-null reading on the Model 662 equal to the correction factor at 0.5 volt.

6-5. REFERENCE VOLTAGE SUPPLY STABILITY TEST.

The reference voltage supply, consisting of the power transformer and the main sup-

a.

ply (printed circuit PC92), is factory calibrated for an output of 500 volts dc greater

than 0.002% . The 500-volt output is adjustable to meet specifications.

If the stability

of the suppLy is not within specifications, then troubleshoot for a faulty component.

/

erence voltage supply.

Routine calibration of the Model 662 does not require a stability test of the ref-

b.

However, a stability test is recommended if one of the components

CALIBRATION

MODEL 662 DIFFERENTIAL VOLTMETER

REFERENCE

VOLTAGE SUPPLY

I I

H tide1 150A

Null

L Detector r

1

Recorder

1

FIGURE: 13.

voltage across the 530-ohm resistor is slightly higher than the standard cell.

LO-kilohm potentiometer to shunt the divider voltage down. See Table 5 for recommended equipment.

in the supply is replaced.

c. For the 24-hour test, the 500-volt output of the reference voltage supply is divi-

ded and .compared to a 1.02-volt saturated standard cell using a sensitive null detector.. Variations between the reference voltage supply and the standard cell are detected b$ the Model L50A and are recorded on a recorder. Refer to Figure 13 for the block diagram of

the test circuit.

Circuit Diagram for Model 662 Reference Voltage Supply Stability Test. The

Use the

All resistors are wirewound.

_j

In using the test circuit, the following points are important.

d.

Saturated standard cells, though extremely stable with time,have a high tempera-

1. ture coefficient and require a controlled environment during use. ton Oil Bath, which is maintained at +35OC rO.Ol°C, is used for the test. Unsaturated standard cells have a lower temperature coefficient,

stability required for this test.

2. The resistor divider network is constructed from wire of the same spool for an extremely close temperature coefficient match (4 ppm, typically).

results when the resistors are immersed in an oil bath to hold the ambient temperature

variations to iO.Ol%.

e. Procedures for the Reference Voltage Supply Stability Test.

1. After the saturated standard cell and the resistor divider network are placed in the oil bath, allowsufficient time for the cell to stabilize at +35’C. Ley Instruments, Inc. ,

the circuit after turning on the 500-volt supply. Set the Model 662 controls as fol-

lows :

or its representative for details.) Connect the standard cell to

but they do not have the long term

Therefore, the Wes-

Additional stability

(Consult Keith-

26

L065R

MODEL 662 DIFFERENTIAL VOLTMETER CALIBRATION

RANGE Switch Reference Voltage Dials

500

4 9 9. 9 9 10 NULL Switch 10 MV POLARITY Switch OFF

Connect the resistor divider network across the Model 662's reference voltage supply,

the positive side of the divider input to the wiper arm of the last Reference Voltage

Switch, S3008, and the negative side of the divider to the LO terminal on the Model 662 front panel.

2. Connect the Model 150A and the recorder as shown in Figure 13. Set the Model 150A to the 3-volt range, Advance the Model 662 POLARITY Switch to + to put 500 volts across the divider. If the Model 150A reads two volts, the standard cell end the divider voltages are improperly connected in series. If the circuit is correct, the Model 150A

will read zero. Increase the Model 150A's sensitivity to the O.l-millivolt range. If

it reads more.than 20 microvolts,

adjust the 500 V CAL potentiometer, R3025 (Figure 22),

shunting the divider.

NOTE

Any adjustment of potentiometer R3025 requires all other ranges to be calibrated.

After a l-hour warm-up, the drift of the entire system should not exceed *25 micro-

3.

volts in 24 hours (Figure 14).

6-6.

OSCILLATOR ADJUSTMENT.

a. The oscillator circuit drives the light modulators. Before adjusting the oscillator,

make sure the reference voltage supply is operating correctly.

Connect the Type 503 Oscilloscope VertFcal Input to the plate and low side of tube

b.

V2OOL (Figure 21) and the Horizontal Input to the Model ZOOCD Oscillator.

Adjust the

oscillator frequency to approximately 42 cps with potentiometer R2007 (Figure 22). The

Model 662 oscillator is then adjusted for minimum meter noise

of 42 cps:

Disconnect the Oscilloscope before adjusting potentiometer R2007. The

- normally within a cycle

Oscilloscope will cause a small loading error.

FIGURE 14.

Stability Strip Chart for Model 662 kcference VoLtage Supply:

are will within rO.O025%.

Note drift is non-cumulative.

No compensation for

Fluctuations

variations

of Line voltage or other conditions was made.

1065R

27

CALIBRATION

MODEL 662 DIFFERENTIAL VOLTMETER

FIGURE 15. Top View of'Mode1 662 Chassis.

Front panel faces to the right.

of components, printed circuits and switches is shown. Parts List for circuit designations.

Figure 16 shows the bottom view.

28

Location

Refer to the Replaceable

126.58

MODEL 662 DIFFERENTIAL VOLTMETER

CALIBRATION

FIGURE 16.

Bottom View of Model

b62

Chassis.

Front panel faces to the right.

ence A in the photograph designates the location of resistors R3031, R3033, R3034,

R3036, R3037 and R3039.

Figure 15 shows the top view.

1265R

Refer-

29

CALIBRATION

MODEL 662 DIFFERENTIAL VOLTMETER

FIGURE 17.

Component Locations on Print

Circuit Board PC93-I..

30

ed

FIGURE 18.

Component Locations on Printed

Circuit Board PC105.

1265R

MODEL 662 DIFFERENTIAL VOLTMETER

CALIBRATION

FIGURE 19.

.”

Locations on Printed Circuit Board PC93-2. Refer to Figure 20 for resist& locations.

Capacitor, Modulator, Diode and Tube

1165R

FIGURE 20. cuit Board PC93-2.

Resistor Locations on Printed Cir-.

Refer to Figure 19 for thr

location of other components.

31

CALDRATSON

MODEL 662 DIFFERENTIAL VOL'JXFXER

FIGURE 21. Capacitor, Modulator, Diode and Tube Locations on Printed Circuit Board PC92. Refer to Figure 22 for the resistor locations.

32

126SR

MODEL 662 DIFFERENTIAL VOLTMETER

CALIBRATION

FIGURE 22. the location of other components.

1265~

Resistor Locations on Printed Circuit Board PC92.

Refer to Figure 21 for

33

CALIBRATION

MODEL 662 DIFFERENTIAL VOLTMETER

34

FIGURE 23. Component Locations of Model 6601A.

to Schematic Diagram 16321B.

Circuit designations refer

,’

1265R

MODEL 662 DIFFERENTIAL VOLTMETER

ACCESSORIES

!-- 1,

SECTION 7. ACCESSORIES

7-l. MODEL 6601A HIGH VOLTAGE DIVIDER.

a. The Model 6601A extends the range of the Model 662 to 5000 volts full scale. The

ratio of the Divider is lOO:l,

error using the Models 662 and 6601A is :0.~02%.

Maximum input into the Model 6601A is 5000 volts.

Set the Model 662 RANGE Switch to 50 volts.

b.

scale. respectively. as outlined in paragraph 2-4.

7-2.

a. The Model 662 is shipped for bench use with four feet and a tilt-bail. The Model

4000 Rack Mounting Kit converts the instrument to rack mounting to the standard EIA (RETMA)

19-inch width.

Connect the RI and LO Divider terminals to the HI and LO Voltmeter terminals,

Connect the unknown voltage to the Divider INPUT, and use the Model 662

RACK MOUNTING. (See Figure25.)

20.01%; the input resistance is 10 megohms. The limit of

NOTE

The meter will read to 5000 volts full

'

To convert the Model 662,remove the four screws at the bottom of each side of the

b. instrument case. Lift off the top cover assembly with the handles: save the four screws. To remove the feet and tilt bail from the bottom cover assembly, turn the two screws~near

the back. The two pawl-type fasteners will release the cover and allow it to drop off.

Remove the feet and the tilt bail and replace the cover (2).

106SR

FIGURE 24. Keithley Instruments Model 6601A High Voltage Divider.

3i

ACCESSORIES

MODEL 662 DIFFEBEHTIAL VOLTMETER

c. Attach the pair of rack angles (3) to the cabinet with the four screws (4) previous-

ly removed.

Insert the top cover assembly (1) in place and fasten to the chassis with the ? -’ two pawl-type fasteners at the rear. Score the top cover with handles, feet and tilt-bail for future use.

7-3.

PLACING IN BACK.

the rack. It is recounnended, however, that a blower be used in the rack

which the Model 662 is mounted.

The Model 662, once converted for rack mounting, easily fits into

enclosure

The instrument specifications state a 0.001% per OC

temperature coefficient. A temperature rises of 5oC (9oF) will cause a 0.005% error.

Item Keithley

See Fig. 25)

1 2

Cover Assembly 14623B 1 Cover Assembly, Bottom (Supplied with

Description Part No. Quantity

Model 662) 14590B

Angle, Rack 14624B

2 5 Front Panel (Supplied with Model 662)

Screw, Slot Head, lo-32 UNC-2 x l/4

(Supplied with Model 662)

e-e

---

TABLE 7. Parts List for Model 4000 Back Mounting Kit.

hrracw

ACOVER ASSEMBLY

in

1 2

4

1

FIGURE 25. parts List.

36

FRONT PANEL

COVER ASSEMBLY

Exploded View for Rack Mounting with Model

4000 Kit.

Refer to Table 7 for

1065R

MODEL 662 DIFFERENTIAL VOLTMETER

REPLACEABLE PARTS

SECTION 8. REPLACEABLE PARTS

8-L. REPLACEABLE PARTS LIST. The Replaceable Parts List describes the components of the

Models

suggested manufacturer, the manufacturer's part number and the Keithley Part Number. last column indicates the figure picturing the part. The name and address of the manufacturers listed in the "Mfg. Code" column are in Table 9.

662

and 6601A. The List gives the circuit designation, the part description, a

The

a-2.

Part Number, the circuit designation and a description of the part,

HOW TO ORDER PARTS.

a. For parts orders,

include the instrument's model and serial number, the Keithley

All structural parts and those parts coded for Keithley manufacture (80164) must be ordered from Keithley Instruments, Inc.., or its representative.

In ordering a part not listed in the Replaceable

Parts List, completely describe the part, its function and its location.

b. Order parts through your nearest Keithley representative or the Sales Service Depart-

ment, Keithley Instruments, Inc.

amp

CbVar CerD camp compv

DCb

EMC ETB ETT

ampere Carbon Variable

Ceramic, Disc Composition Composition Variable

Deposited Carbon Electrolytic, metal cased

Electrolytic, tubular

Electrolytic,

tantalum

MtF Metal Film Mil. No.

MY

n

Poly P

I-(

Military Type Number Mylar

ohm

Polystyrene

pica (10-12)

micro

(10-6)

v volt

f farad Var Variable

k kilo (103) w watt

ww Wirewound

M or meg

mega (106) or megohms WWVar

Wirewound Variable

m milli (10-3) Mfg.

Manufacturer

TABLE 8.

Abbreviations and Symbols.

0665

37

REPLACEABLE PARTS

(Refer to Schematic Diagram 1855lE for circuit designations.)

MODEL 662 DIFFERENTIAL VOLTMETER

MODEL 662 REPLACEABLE PARTS LIST

CAPACITORS

Circuit

Desig. Value Rating c1001

Cl002 Cl003 Cl004 Cl005

Cl006 Cl007 Cl008 Cl009 Cl0 10

Cl0 11 Cl012 Cl013 Cl014 Cl0 15

Cl016 Cl017 Cl018 Cl019 Cl020

.05 I.rf .47 pf

0.1 vf O.lpf

0.1 kf

0.05 I.rf

-05 pf

10 I.rf

.002%f

10 I.lf 680 pf

40 Pf

0.0022~f 10 wf .0047 IJ.f

1.0 IJ.f

4 wf

100 pf

600 wf

20 iJf

1600 v 600 v 100 " 100 v 100 "

100 v 600 v 15 " 1000 " 15 v

1000 "

450 v

1000 " 15 v 1000 "

600 v 250 " 15 v 6v 450 v

Mfg. Mfg.

Type MY

MY

Code

14655

14655 Poly 00656 Poly Poly

00656 00656

Poly 00656

MY

ETB

56289

56289 CerD 72982 ETB 56289

CerD 72982 EMC 56289

CerD ETB CerD

ETB ETB

72982

56289

72982

13050 24009

14655

ETB 56289 ETT EMC

05079 56289

Keithley

Part No. Part No.

Fig.

Ref.

DPMS16S5 C87-.05M 16 WMF6P47 ClOl-.47M

16 lPJ-104.J c129-.lM 18 lP.T-104.J C129-.lM lPJ-1045 c129-.lM

lPJ-503J

C129-.05x

18

18 CPS-s50 C62-.OSM 19 TE1155 C3-10M 19 I' 851ZW222P c22-.0022M

TE1155 C3-10M 801X5R681K C22-68OP

TVL2762 C36-40/20M 851Z5V222P TE1155 81lZSV472P

c22-.0022M C3-10M C22-.0047M

C12-1M BBR4-250 C27-4M TE1162 C3-100M

TEZ600-6C2 C133-600M TVL2762 C36-40/20M

19 19

19 19 19 19 19

19 " 19 19 19 19

'?

c2001 moo2

c3001 C3002 c3003 c3004

c3005 C3006

c3007 C3008 c3009 c3010

c3011

38

.Ol pf .OL wf

20 pf 20 pf

.OOl pf

1.0 wf

0.05 pf 4 Pif

50 pf

.0047 r.rf .022 pf .05 Kf

40 pf

400 "

400 " 450 v

450 "

1000 v iooo " 600 v

250 v 6v 1000 " 200 " 600 v

450 "

Poly Poly

EIMC EMC CerD 72982 ETB

MY

14655 14655

wMF4Sl C114-.OlM wm4Sl c114-.olM

37942 FP144 56289

TVL2762

801Z5VlO2P C22-.OOlM

13050

56289

Z4009B C14-1M

6PS-S50 C62-.05M

ETB 14655 BBR4-250 ETB CerD ETB

MY

ETMC

56289 72982

13050

56289 56289

TEllOO C17-50M

8llZ5V472P C22-.0047M

MWlA C6-.022M

6PS-S50 C62-.05M

TVL2762 C36-20/40M

C36-20M C36-20/40M

C27-4M

21

21 21

21

21 22

21 21 21

21

0665

MODEL 662 DIFFERENTIAL VOLTMETER

REPLACEABLE PARTS

DIODES

Circuit Desig.

DlOOl D1002

D3001 03002 D3003

Circuit Desig. Description

BTlOOl Battery, 1.34-v mercury (Mfg. No. PX13T2) 37942 BA-16 DSlOOl Neon Lamp (Mfg. No. NE-al) DS2001 Neon Lamp (Mfg. No. NE-2P)

DS2002 Neon Lamp (Mfg. No. NE-2P) 08804 PL-2 DS2003 DS2004 Neon lamp (Mfg. No. NE-2P) 08804 PL-2

Type

Silicon Silicon

Silicon Silicon Zener

Neon Lamp (Mfg. No. NE-2P)

Number

1~645 lN3256 02735

lN2378 08520 lN3256

-

MISCELLANEOUS PARTS

Mfg.

Code

01295

02735

80164

Keithley Part No.

RF-14 RF-22

RF-25 RF-22 DZ-8 (1)

Mfg.

Code Part No. Ref.

08804 08804 PL-2 08804 PL-2

Keithley

PL-7

Fig. Ref.

:; 21

21 21

Fig.

18 ' la

15 15 15

15 DS3001 Neon Lamp (Mfg. No. NE-2P) (on older models) 08804 PL-2 El001 Light Modulator Assembly 80164 Model 1513

El002 Light Modulator Assembly 80164 Model 151.3 El003 Light Modulator Assembly 80164 Model 1514

E3001 Light Modulator Assembly 80164 Model 1512 E3002 Light Modulator Assembly 80164 Model 1512

FlOOl (117 v) FlOOl (234 v) Fuse, slow blow, 0.5 amp (Mfg. No. 312.500)

-

JlOOl

J1002 51003 .I1004

51005 31006

Ml001 80164 ME-38

PLO01

Fuse, slow blow, 1 amp (Mfg. Type MDL)

Fuse Holder (Mfg. No. 342012)

Binding Post, HI (Mfg. No. DF31RC) Binding Post, LO (Mfg. No. DF31BC) Binding Post, LO (Mfg. No. DF31BC) Binding Post, GND (Mfg. No. DF31BC)

Shorting Link (Mfg. No. 938-L)

Banana Jack, + (Mfg. No. 108-745-l) Banana Jack, - (Mfg. No. 108-745-z)

Meter

Power Cord, 6 feet (Mfg. No. 4638-13) 82079

71400 Fo- 10 75915 FU-6 75915

58474 58474 58474 58474 BP-8B 24655 BP-6

74970 BJ-3 74970 BJ-4

FH-3 BP-8R

BP-8~ BP-8B

co-2

eta

la

19

21

3

2 2 2

2

3

15

3

SlOO 1

(1) Refer to paragraph 5-6.

0665

Rotary Switch less components, NULL 80164 Knob Assembly, Null Switch 80164

SW- 115 148388

2

33

REPLACEAXEPARTS

MODEL 662, DIFFERENTIAL VOLTMETER

circuit

Desig. Description

Knob Assembly, Meter Zero Potentiometer

s3001

53002 53003

s3004

s3005

S3006

Topple Switch, Power (Mfg. No. 20994LH)

(on newer models) Slide Switch, 117-234 Switch Assembly with components, Readout

Dial Assembly, O-4 Readout

Switch Assembly with components, Readout

Dial Assembly, O-9 Readout Switch Assembly with components, Readout

Dial Assembly O-9 Readout Rotary Switch less components, Readout

Dial Assembly, O-9 Readout

MISCELLANEOUS PARTS (Cont'd)

Mfg.

Keithley

Code Part No. 80164 15110A

04009 SW-4

80164 SW-151 80164 18479B

80164 14827A

80164 17046B 80164

80164

148288 17073B

80164 148288 80164 SW-118

80164 148288

Fig. Ref.

2

'7

.'

s3007

S3008

s3009

s3010

T3001 TC3001

Circuit Desig.

RlOOl R1002 Rloo3 R1004 Rl005

R1006 R1007 R1008 R1009

RlOLO

Rotary Switch less components, Readout

Dial Assembly, O-9 Readout Rotary Switch less components, Readout

Dial Assembly, O-10 Readout Rotary Switch less components, POLARITY

Knob Assembly, Polarity Switch Rotary Switch less components, RANGE

Knob Assembly, Range Switch Transformer Oven (on older model)

RESISTORS

Value

LOO I$-l 1 kn

50 m

1.5 al

5 kn 50 kQ

505 kn

12.5 Mn

1.14 Mfl

,220 kr,

Rating

20%, L/2 w LO%, L/2 w L%, 2 w l%, L/2 w L%, l/2 w

l%, l/2 w L%, L/2 w L%, lw L%, l/2 w

LO%, l/2 w

Type

camp

corn;

DCb 91637 DCb 79727 DCb 79927

DCb 79727 DCb DCb 91637 DCb

Comp

80164 80164

80164

80164 80164

80164 80164 80164

Mfg.

Code

75042

Mfg.

Part No. Part No:

GBT R37-LOOM 16

01121 EB,

DC-2

CFE-15

CFE-15 CFE-15

79727 CFE-15

DC-1

79727 CFE-15 01121 EB

SW-118

2

148288

SW-127 148298

SW-119 148388

SW-116 14838A

TR-67

15

ov-1

Keithlev Fie.

Ref.

Rl-1K R14-50M R12-1.5M R12-5K

RlZ-50K RlZ-505K R13-L2.5M R12-1.14M

Rl-220K

16 17 17 17 17 17 17 17

18

-?

../

40

0665

MODEL 662 DIFFERENTIAL VOLTMETER

REPLACEABLE PARTS

(T i

( :

circuit Desig. Value Rating

RlOll R1012 Rl013 R1014

RlOL5 R1016

R1017 R1018 RlOL9 R1020

RL021 R1022 R1023 R1024 R1025

R1026 R1027 R1028 R1029 R1030

220 IQ 220 kn

3kD 3 kl

900 Ml

'15 ko

200 k.0 470 kfl

1MC

22.wl

1.5 MC 10 kn

1.5 LG 15 kn 10 m

70 ko 450 kfi

4MQ

10 m

1.5 im

lO%, l/2 w 10%; l/2 w l%, l/2 w l%, l/2 w l%, l/2 w

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

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

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

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

RESISTORS (Cont'd)

Mfg.

Type

camp 01121 EB

Comp 01121 EB Rl-220K 18 DCb 79127 CFE-15 RlZ-3K DCb 79727 CFE-15 R12-3K 18 DCb

wwvar DCb DCb

camp

Comp

camp

Comp

Comp Comp

DCb DCb DCb Comp Comp

Code

79727 CFE-15 R12-900K 71450

79727

79727 01121 01121

01121 01121 01121 01121 01121

79727

79727 01121 01121

Mfg. Keithley

Part No.

AW

CFE-15 CFE-15 R12-470K 18 EB Rl-1M 18 EB Rl-22M

EB Rl-1.5M EB EB Rl-1.5M EB EB

CFE-15

CFE-15 Rl2-450K

CFE-15

EB

Part No. Ref. Rl-220K

RP3-15K

R12-200K

Rl-1OK Rl-15K

Rl-1OM RlZ-70K R12-4M

Rl-LOM Rl-1.5M

Fig.

18

18 18

2

18

20 20

20 20 20 20

:: 17 20 20

R1031 R1032 R1033 R1034 R1035

R1036 R1037 R1038 R1039 R1040

R1041 Rl042 R1043 R1044 R1045

R1046 R1047 R1048

\ R2001

,, .?'

R2002 R2003

8.2 kD 100 kn

3.3 MO 10 Mfl

100 k,Q

1.2 kn 220 kn 10 kl 2kfl

a40 kQ 't400 kQ

>+4.7 Ml-l

500 n

1.5 kQ 200 n

80

n lkn LkQ

220 kn

1.8 MO, 100 kQ

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

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

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

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

20%, .2 w LO%, L/2 w

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

Comp Comp Comp Comp Comp

Comp Comp Comp

ww

DCb DCb

DCb War ww WWVar

ww

Comp

compv

Comp DCb

camp

01121

01121 01121 01121 01121

01121 01121 01121 01686

79727

71450 01686

71450

01686 01121

71450

01121

79727

01121

EB EB EB Rl-3.3M EB EB Rl-100K

EB Rl-1.2K EB Rl-220K EB Rl-1OK E-30 CFE-15

CFE-15 RlZ-400K CFE-15

AW

E-30

P252

E-30 R58-80 EB

70 EB

CFE-15 RlZ-L.BM EB Rl-100K

Rl-8.2K 20 Rl-100K

Rl-1OM

R58-2K R12-40K

RlZ-4.7M RP3-500 R58-1.5K RP22-200

Rl-1K RP3L-1K

Rl-220K

20 20 20 20

20 20 20 18 17

17 17 20 20 3

20 20 20

22 22 22

4 Nominal value, factory set.

0665

41

RX7?LACEASLE PARTS

MODEL 662 DIFFBXENTUL VOLmTER

Circuit Desig. Value

R2004 R2UO5

RZJO6 R2007 R2008 R2009 R2010

RZ.011 R2012 R2013

R3OOL R3002 R3003 R3004 R3005

150 krl 150 kn

1.8 IQ 50 m 40 m

150 k5-l

180 ko LOO kn

100 kn 220 ko

220

iz

50 ko 820 k!l 150 kn

1m

Rating

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

L%, L/2 w

30%, L/2 w

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

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

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

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

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

R3SISTORS

Type

coulp

camp DCb

compv DCb DCb DCb 79727

camp 01121 Comp Comp 01121

Comp ww Comp Comp Comp

(Cont'd)

Mfg. Code

01121 01121

79727 71450 VA-45 RPL6B-50K 79727 CFE79727

01121 EB Rl-100K

01121

91637 RS-5 01121 EB Rl-820K 01121 01121

Mfg.

Part No. EB Rl-150K

EB Rl-150K CFE-15 R12-1.8~

15

CFE-15 R12-LSOK CFE-15

'EB

EB ' Rl-220K EB

EB EB

Keithley Part No.

R12-40K R12-180K Rl-100K

Rl-220 R4A-50K 22

Rl-150K Rl-1M

Fig.

Ref. 22

22 22

22 22 22 22

22‘ 22 22 ,I

22 22

,3

R3006 R3007 R3QO8 R3009 R3010

R3OLL R3012 R3013 R3014 R3015

R3016 R3017 P.3018 R3019

R3020

R3021 R3022 R3023 E3024 R3025

lM(a

3.3 kn

1Mn 470 0. 470 kn

L&-2

4.7 kn

LNl

10 MO 330 kfl

680 kn

270 k~

2.2 MO

5.6 ko

65.4 ko 1MC-l

220 ko

12.5 ko

125 ko 200 n

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

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

lO%, l/2 " lO%, l/2 " lO%, l/2 "

lO%, l/2 w

O.L%, 50 w

lO%, l/2 "

LO%, l/2 w O.l%, 2 w O.l%, 2 w

lO%, 5 w

Comp 01121 Comp 01121 Comp 01121 Comp Comp

Comp 01121

Comp 01121 Comp 01121 Comp

Comp Comp 01121

Come. Comp

ww

Comp Comp

ww ww war 71450

01121 EB RL-470

01121.

01121

01121 01121

91637

01121 01121

80164 80164

EB Rl-1M EB Rl-3.3K EB

EB

EB EB EB RI-1M EB Rl-LOM EB Rl-330K

EB Rl-680K EB Rl-270K EB Rl-2.2M EB

RH-50 EB

EB Rl-220K

RL-LM RL-470K Rl-LM

Rl-4.7K

Rl-5.6K R73-65.4K

Rl-1M

I:;

AW

RP34-200

16 22 \

22 -1'

22

22 22

22 22 22

22

22 22 22

15 22

22 22 22 22

X3026 R3027 F.3028

x3029

R3030 * Nominal value, factory set, Refer to paragraph 5-6.

(1) R3023, R3024 and R3026 comprise a matched set, Keithley Part No. 183708.

42

4.4 kn *

Y<

1k-l

250 kQ

O.l%, L/4 w O.l%, l/4 w O.l%, L/4 w

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

ww 80164 NW 01686 ww DCb ww

01686

79727

01686

7009 7009 CFE-15 7070

(1)

R95-" R95-'* R12-1K R93-250K

22 22 22

22

0665

MODEL 662 DIFFERENTIAL VOLTMETER

..~

Circuit Desig. Value

Rating

RESISTORS (Cont'd)

Mfg.

Type

Code Part No. Part No. Ref.

Mfg.

REPLACEABLE PARTS

Keithley

Fig.

R3031 R3032 R3033 R3034 R3035

R3036 R3037 R3038 R3039

9 k-i

:2?3 kfi

91 kl

lksl

2.563 ksl

930 ko

1 kn

250.9 n

L%, l/%,,w LO%, 5 w

O.l%, l/2 w

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

O.l%, l/2 w

l%, l/2 w LO%, 5 w

O.l%, l/2 w

DCb WWVar ww

79727 71450 80164

DCb 79727

WWVar

71450

ww 80164

DCb WWVar ww

79727 71450 80164

CFE-15

AW

CFE-15

AW

CFE-15

AW

RL2-9K 16 RP34-1K

(2)

Rl2-91K RP34-1K

(2)

R12-930K RP34-1K

(2)

22 16

16

22 16

16 22 16

R3040 to

R3045

40 k0.

0.02%, 1 w

ww

80164

(3)

15

R3046 to

R3056

8kn

0.02%, 1 w

ww

80164

(4)

15

R3057 to

R3067

1.6 kn

0.05%, l/2 w

ww

80164

(5)

15

R3068 to

I

R3078

320 n

O.l%, l/2 w

ww

01686 7044 R67-320

15

R3079 to

R3089

64 n

O.l%, l/2 w

ww

01686 7044 R67-64

15

R3090 to

R3099

R3100

12.8 n

woo n

O-l%, l/2 w

lO%, l/2 w

ww

Comp

01686 7044 R67-12.8 01121

EB

Rl-100

VACUOM TUBES

Circuit Desig.

Number Coda

Mfg. Keithley

Part No.

VlOOl 12AK7 73445 EV-12AK7 v1002 6~~8 00011 w- 6cM8

v2001 12AU7 73445 EV-12AU7

*Nominal value, factory set.

(2) R3033, R3036, and R3039 comprise a matched set, Keithley Part No. 15432A. (3) Part of assembly with S3003, Keithley Part No. 18479B (4) Part of assembly with 53004, Keithley Part

No.

17046B

(5) Part of assembly with 53005, Keithley Part No. 17073B

15

Fig. Ref.

19 19

21

0665

43

RBPI&EASLEPARTS MODEL 662 DIFFERENTIAL VOLTMETER

VACUUM TUBES (Cont'd)

Circuit De&g.

v3001

v3002

v3003 v3004

v3oos

Circuit

Desig.

.I101

.Tl02

3103

Mfg.

Number

12Ax7 12Ax7 12Ax7 ml6

OG3

MODEL

(Refer to schematic Diagram 16321B for circuit designations)

Description Receptacle, hn modified

Plug, hn, Mate of JlOl, Mil. No. UG-59A/U

(Mfg. No. 7908)

Binding Post, HI OUTPUT (mfg. No. DF31RC) 58474 BP-8R

Binding Post, LO OUTPUT (Mfg. No.

6601A REPLACEABLE PARTS LIST

code 73445

73445

73445.

00011

73445

TEBMINALS

DF31BC) 58474

RESISTORS

Keithley

Part No. N-12AK7

N-12AK7

EV-12.4X7

EV-6CMG

EV-OG3

Mfg.

Code Part No. 80164

91737

Keithley

cs-79 CS-80 23

BP-8~

Fig. Ref.

21 21 21 21 21

Fig. Ref. '

23

23 23

Circuit

Desig. RlOl

R102 Rlo3 R104 R105

R106 R107 R108

"Nominal value, factory set.

30011

30656 Aerovox Corp.

New Bedford. Mass.

Value Rating

2Mn O.l%, 1 w 2MC O.l%, 1 w 2MC O.l%, 1 w 2MD O.l%, 1 w 2?%l O.l%, 1 w

200 n lO%, 2 w 100 kn O.l%, 1 w

kl ko.

Sylvania Electric Products, Inc. 01121 Buffalo Operations of Sylvania Electronic Systems Buffalo,

N.

Y.

1%. l/2 w

Mfg.

Type

ww 54294 PL16 ww 54294 ~116 WV 54294 PL16 ww 54294 Pl16 ww 54294 Pll6

War 71450 AW

ww 54294 P-36 Deb

Code

79727

01295

Allen-Bradley Corp. Milwaukee, Wis.

Texas Instruments, Inc. Semi-Conductor-Components Division

Dallas, Texas

Mfg. Part NO.

CFE-15

Kefthley

Part No.

R91-7.M 23 R91-2M 23 R91-2M

R91-'2M

R91-2M RP3-200

R90-1OOK.~ 23 R12-1K

Fig.

Ref.

23 23 23

23 23

TABLE 9 (Sheet 1).

for Manufacturers, Cataloging Handbook H4-1.)

44

Code list of Suggested Manufacturers.

(Based on Federal Supply Code

0665

MODEL 662 DIFFERENTIAL VOLTMETER

REPLACFABLE PARTS

11686 RCL Electronics, Inc.

Riverside, N. J.

71400

Bussmann Mfg. Div. of

McGraw-Edison Co.

St. Louis, MO.

12735 RCA Semiconductor and Materials

Division of Radio Corp. of America 71450 CTS Corp. Somerville, N. J.

Elkhart, Indiana

14009 Arrow-Hart and Hegeman Electric Co. 71590 Centralab Division of

Hartford, Connecticut

Globe-Union, Inc.

Milwaukee, Wis.

14713 Motorola, Inc.

Semiconductor Products Division 72982 Gudeman Co. Phoenix, Arizona

Chicago, Illinois

15079 Tansitor Electronics, Inc. 73445 Amperex Electronic Co. Division

Bennington, Vt.

of North American Philips Co., Inc Hicksville, N. Y.

18520 Electronic Devices, Inc.

North Ridgeville, Ohio 74970 Johnson, E. F., Co.

Waseca, Minn.

18804 Lamp Metals and Components

Department G. E. Co.

Cleveland, Ohio

75042 International Resistance Co.

Philadelphia, Pa.

13050 Potter Co.

75915 Littelfuse, Inc.

Wesson, Miss. Des Plaines, Ill.

14655 ,Cornell-Dubilier Electric Corp.

Newark, N. J.

15909 Daven Co.

Livingston, N. J.

24655 General Radio Co.

West Concord, Mass.

37942 Mallory, P. R., and Co., Inc.

79727 Continental-Wirt Electronics Corp.

Philadelphia, Pa.

80164 Keithley Instruments, Inc.

Cleveland, Ohio

81483 International Rectifier Co.

El Segundo, Calif.

82879 Royal Electric Corp.

Indianapolis, Ind. Pawtucket, R. I.

53021 Sangamo Electric Co. 85599 Tube Department G: E. Co.

Springfield, Ill. Schenectady, N. Y.

54294 Shallcross Mfg. Co.

91637 Dale Electronics, Inc.

Selma, N. C. Columbus, Nebr.

56289 Sprague Electric Co.

91737 Gremar Mfg. Co., Inc.

North Adams, Mass. Wakefield, Mass.

58474 Superior Electric Co., The

Bristol, Corm.

TABLE 9 (Sheet 2).

Code List of Suggested Manufacturers.

Code for Manufacturers, Cataloging Handbook H4-1.)

45

(Based on Federal Supply

1065R

1

-

I

Tektronix 662 Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual