Keithley 427 Service manual

INSTRUCTION MANUAL

MODEL 427

CURRENT AMPLIFIER

0 1975, KEITHLEY INSTRUMENTS, INC.

CLEVELAND, OHIO, U.S.A.

DOCUMENT NUMBER 29103

CONTENTS

CONTENTS

1. GF,Ng3,&.L DESCRIPT~ON-------------------------------.-------- 1

2.

OPERATION-------------------------------------------------- 4

MODEL 427

3. APPLICATIONS----------------------------------------------- 9

ACCESSORIES------------------------------------------------ 10

4.

5. ClRC"IT DESCRIPTION---------------------------------------- 12

6. REp~Cp‘&LE PARTS------------------------------------------ 17

7. CALIBRATION------------------------------------------------ 26

SCNEMATICS---------------------------------------------------- 33

1074

MODEL 427

ILLUSTRATIONS

ILLUSTRATIONS

Figure No. Title

1 Front panel. __-___---___-_____-___________________ 1
2 Front pane1 Controls. ________--______-____________ 3
3 Rear Panel Controls. - 3
4 shunt Method Measurement, -----------------__------ 4
5 Effect of Shunt capacitance. ---------------------- 4
6 Compensation for Shunt Capacitance. --------------- 5
6b Extended Frequency Response. ---------------------- 5
7 Fee&a& Method. _--__-_-__________-_______________ 6
8 Input Voltage N&se. -------------___-------------- 6
9 Bandwidrh of Feedback System. --------------------- 7
9b Effect of filter on Noise spectrum. -------------- 7

9, Effect of Input Capacitance on Noise. ------------- 7
10 Frequency Compensafian. ---------_____--_-__------- 7
11 Plot of Noise-Improvement Contours.
12 Block Diagram of a High-Speed Current Amplifier, -- 12

__- _____ -__-__

Page

9

13 Filter circuit. ------_______--_-__-_______________ 13
14 power s”pp~y Regulator. --------------------------- 13
15 current suppression. ------------__---------------- 13
lb COmpOnent Layout - PC-291. ------------------------ 13
17 component Layout - pc-290, -----------------___---- 14
18 component Layout ­19 COmpOnenf Layout ­20 chassis - Top vie”. ------------___--------------- 16
21 Chassis Assembly - Exploded “few. ----------------- 19
22 Bottom CO”er Assembly. -------------------------- 19
23 Measurement of Input Voltage Drop. ---------------- 27
24 Measurement of Rise Time. -------_--_____-___-_____ 28
25 Measurement of Filter Rise Time. ------------------ 29

pc-2?39.
P&292.

---------_------___-____ 15

---------------__------ 15

1074

iii

SPECIFICATIONS

SPECIFICATIONS

RANGE: 10’ to 10” volts/ampere in eight decade ranges.

(10-13 ampere resolution to 10.” ampere full output).
OUTPUT: *10 volts at up to 3 milliamperes.
OUTPUT RESISTANCE: Less than 10 ohms dc to 30 kHz.
OUTPUT ACCURACY: 12% of reading to the lo9 vattsl

ampere range, +4% of reading on the 1O’O and 10”

volts/ampere ranges exclusive of noise. drift and current

offset.

RISE TIME (10% to 90%): Adjustable in lx and 3.3x steps

from “Fast Rise Time” listed below to 330 rnsec.

NOISE VS. RISE TIME’:

I

FAST RISE TlML

MODEL 427

STABILITY: Current offset doubles per 10°C above 25°C.

Voltage drift is less than 0.005% per “C and less than

0.005% ,,er da” of full outDut after l.hour warmur,.

OFFSET CURRENT: Less than lQLz am&e at 25”C’and up
CURRENT SUPPRESSION: lo-lo ampere to 10-a ampere in

OVERLOAD INDICATION: Lamp indicates pre-filter or post.

CONNECTORS: Input: (Front) ENC. Output: (Front and

DIMENSIONS; WEIGHT: Style M 3%” half.rack, overall bench

,-

to 7001, relative humidity.

eight decade ranges with 0.1% resolution (lO.turn poten.

tiometer). Stability is +O.Zo/. of suppressed value per “C
bO.Z% per day.

INPUT VOLTAGE DROP: Less than 400 /.IV for fullaxle

output on the 10” to 10” volts/ampere ranges when

properly zeroed.

EFFECTIVE INPUT RESISTANCE: Less than 15 ohms on the

10” and 105 volts/ampere ranges. increasing to less than

4 megohms on the 10” volts/ampere range.

MAXIMUM INPUT OVERLOAD: Transient: 1000 volts on any

range for up to 3 seconds using a Keithley (or other 10
mA-limited) highaoltags supply. Continuous: 500 volts
on the 10” to 1O’voltsjampere ranges, decreasing to ‘ZOO
an the 10”. 70 on the lo5 and 20 volts on the 10’ volts,
ampere ranges.

filter overload.

DYNAMIC RESERVE: 10 (20 dB).

Rear) BNC.

POWER: 90.125 or 180.250volts (switch selected), 50.60 Hr.

5 watts.
size4’~highx8%‘widex12L/a”deep(100x217 x310 mm).

Net weight, 7 Ibs. (3.0 kg).

i”

1074

MODEL 427

GENERAL DESCRIPTION

SECTION 1.

l-1. GENERAL; The Model 427 Current Amplifier is a
high-speed, feedback-type amplifier with particular
features useful for automated semiconductor testing,

mass spectrometry, and gas chromatography applications.

l-2. FEATURES.

a. Wide Dynamic Range. Selectable rise times permit
low-noise operation important when resolving small
current levels.

b. High Speed.
out of a 10sSZpere signal with a 100 microsecond
rise time.

Typical resolution is 20 picoamperes

GENERAL DESCRIPTION

C. Built-in Current Suppression.
the signal level can be measured since large ambient
current levels can be easily suppressed.

d. Overload Indication.
assured since overloads are automatically indicated.

e. Variable Cain. The GAIN Switch is designated
in eight gain positions from lo4 to 1011 volts per
ampere - therefore gain adjustment is straight forward.

f. Variable Kise Time. Optimum response can be
selected for each gain setting since a separate RISE

TIME switch is provided on the front panel.

Small changes in

Accurate measurements are

0471

1

GENERAL DESCRIPTION

MODEL 427

TABLE 1-l.

Front Panel Controls and Terminals

PUSH Power Switch (S302)
GAIN Switch (5201)
RISE TIME (5101)
SUPPRESSION

MAX AMPERES Switch (S303)

FINE Control (R333)

POLARITY Switch (5304)

ZERO ADJ Control (R235)

INPUT

Receptacle

OUTPUT Receptacle (5102)

~ OVERLOAD Indicator (DS302)

(5202)

Functional Description

Controls power to instrument.
sets gain in Volts per ampere.

Sets

rise time Fn milliseconds.

Sets maximum suppression.

Adjusts suppression.

Sets polarity of suppression.

Adjusts output zero.

Input source connection.

Output connectFon.

Indicates overload condition.

Rear Panel Controls and Terminals

TABLE 1-2.

Paragraph

2-4, al
2-4, a2

2-4, a3

2-4, a4
2-4, a5
2-4, a6
2-4, a7
2-3, a
2-3, b

2-5, d

Control or Terminal Functional Description Paragraph

Line Switch (5301)

Power Receptacle

Fuse (F301)

0lJTPuT Receptacle

(P305)

(5103) Output connection.

Sets instrument for 117V or 23411.
Connection to line power.
Type 3AG Slow-Blow, 117V @ l/4 A (w-17)

234V @ l/S A (w-20)

WARNING

Using a Line Power Cord other than the one supplied

with your instrument may result in an electrical

shock hazard. If the Line Power cord is lost or
damaged,

replace only with Keithley Part No. CO-7.

2-4, b
2-3, c

2-3, b

0878

MODEL 427

GAIN

SWITC

S20

,----SUPPRESSION-,

FINE

ADJUST

GENERAL DESCRIPTION

POLARITY

SWITCH

INPUT

5202

ZERO ADJ

R235

FIG"RF 2.

OVERIDAD Power

.

DS302 S302

want Panel Controls.

P

OUTFW

5102

I

0471

FIGURE 3.

Rear Panel Controls.

OPERATION

MODEL 427

SECTION 2.

MEASUREMENT CONSIDERATIONS.

2-1.

a. Current-Detection Devices.

‘small electrical c~rrent8 has been the basis for a

number of instrumental methods used by the analyst.
Ion chambers, high-impedance electrodes, many forms
of ch=“metog=aphic detectors, phototubes and multipli­ers are coaronly-used t=ansduce=a which eequire the
measurement of small currents. Devices used for this
measurement a=e often called electraaeters.

b.. In any measure-

ment, if e”“=ce noise greatly exceeds that added by

the inst=“mentatian, optimization of instrumenteti””
is unimportant.
ical minimum, optimization of instrumentation charac-

teristics becomes imperative. TO determine the cate­gory into which this meas”=ement falls. the researcher
needs t” be familiar with the characteristics which

impoee theoretical and practical limitations on his
me*surement .

theoretical limitations present in voltage measueements

The noise inceeases with 8”“=ce realstance, and the

familiar equation for the mean-square noise voltage is

q = 4kTRAf Eq. 1

When source noise approaches theoret-

Most researchers a=e familiar with the

The DleasUrement of

OPERATION

Prom this equation it is irmnediately apparent that the
m%QB”rement of emall current =equi=es large values of
R, i.e., high impedance levels. Howwee, thfe gives
difficulties for meas”=ements requiring wide bandwidths
because of the RC time constant associated with a
high-megohm resistor and even a few picofarads of cir-

cuit capacitance.
generating a voltage across a parallel RC. The fre­quency response of this current measurement is limited

by the RC time constant.

end the -3 dB p”int “CC”=B at a frequency

Lor* noise and high

requirements.
techniques must be used which obtain high speed “sing

high-impedance devices.

C. Hiah Speed Methods.

1. High epeed can, af c”“=se, be obtained in .

shunt-type meae”=eme”t by “sing a low value for the
shunt resist”=.
resistor value int=ad”ces excessive noise into the

meQ8”rement.

Figure 4

speed,

TO optimize a current-measuring system,

As pointed ““t above, such a srmll

shows a c”==ent s”“=ce

Figure 5

therefore, a=e contradictory

shows this response

whe=e k is the Boltzma”” Constant, T ia the absolute

temperature of the s”“=ce resistance R, and
noise bendwidth( 3

single RC rolloff.) In the case of cureent measure-

ments it Is more appropriate to consider the noise

current generated by the ~l”“=ce and load resistances.
The mean squaee noise c”==ent generated by a resistor

is given by Eq. 2.

FIGURE 4.

In the shunt method c”=re”t is measured by

the voltage drop ac=“ee a resistor.

times the 3 dB bandwidth for a

Af

is the

2. A second method to achieve bandwidth is to
keep R large, to accept the frequency roll-off
starting at F”, and t” change the frequency eesponae
of the voltage amplifier a8 ehown in Figure 6a. The
combined effects of the RC time c”“sta”c folloved
by this amplifier is shown in Pigure 6b and it is
seen that the frequency response of the c”==ent

measurement has been extended to Pl. The frequency

at which the amplifier gain sta=‘ts to increase must
be exactly equal t” the frequency F” determined by
the RC time c”nstant in order for this approach t”
result in a flat frequency respanse. Therefore,

FO

FIGURE 5. The frequency respanse of the shunt method

1s limited by omnipresent ahunt capacitance.

LOG FREQUENCY

I

0471

MODEL 427

OPERATION

this oethad is ueeful only far application* where
the shunt capacitance C is constant. Aaide from
thin drawback this is * 1eSitimste approach which
is being wed in low-noise, high-speed current-

meesuring applicatians. In addition to current noise

in the *hunt and in the amplifier input stage, B

maJor source of noise in this system *ri*** from

the voltage-noise generator ssaociated with thb in­put atage (reflected a* current noise in the shunt
resistor) caused by the high-frequency peeking in
the following stages of amplification. More will be
said about this in the discussion on noise behavior.

3. A third method used for speeding up * current

measurement asas guarding techniques to eliminate

the effects of capacit*nces. Unfortunately only

certain type* of capacitance*, such ** cable cap=-

itances, can be conveniently eliminated in this

manner.

itences associated with the *ource itself became*

very cumbersome and m*y not be feasible in many in-

stsnces.

*re identical to those mentioned in the second

system.

4. A fourth circuit configuration combines the
capability of low-noise and high-speed performance
with tolerance for varying input C and eliminate*
need for separate guard by making the ground plane
*n effective guard. This is the current-feedback
technique.
ment of 3 over shunt technique*. Again, the major
sources of noise are identical to those mentioned

in the second system.

d. Noise in Current Measurements. Noise forms *

b*aic limitation in *nv hinh-speed current-measurinn

system. The shunt *y&m give; the simplest curren;

measurement but does not give low-noise performance.

A properly designed feedback *y*tem gives superior

noise - bandwidth performance. Noise in these two

systems will be discussed next.

1. Noise Behavior of the Shunt System. High
speed end low noise *r* contradictory requirements
in any current meesurement because *orw capacitance
is always present. The theoretical performance
limftetion of the shunt *yetem c*n be calculated **

To eli,r,inate the effect of parasitic c*p*c-

The major *ourc** of noise in this *“*tern

This technique gives * typical improve-

The rms thermal noise current (in) generated by *
resistance R is given by

Eq. 4

The equivalent noise bandwidth (.f) of * parallel SC
combination is Af = 1/(4RC) snd the eignal hand­width (3 dB bandwidth) F, = 1/(2nRC). For practical

purposes peak-to-peak noise is taken 88 5 times the
ml* value. The peak-to-peak noise current can now

be written a*

i

UPP =

In practice, e typical value for shunt cape.cit*nce

is 100 picofarads.
rule-of-thumb is obtained. The lowest ratio of

detectable current divided by signal bandwidth using

*hunt-techniques is 2-10-14 ampere/Hertz for B peak­to-peak signal-to-noise ratio equal to 1. A coroll-

ary far this rule-of-thumb expresses the noise cur-

rent in term* of obtainable risetime (lo-SO% rise­time tr = 2.2 RC). The lowest product of detectable
current and risetime using shunt technique* is 7 x

lo-l5 ampere seconds.
assumed that the voltage amplifier does not contri­bute noise to the measurement.

2. Noise Behavior of the Feedback System. There

are three *ource* of noise in the feedback system

that have to be looked at closely. The firat two,

input-stage shot noise and current noise from the
mea*urinS resistor, are rather straight-forward. The

third, voltage noise from the input device of the
amplifier, cau*e* *ome peculiar difficulties in the
measurement. Any resistor connected to the input

injects white current noise (Eq. 4). In the circuit
of Figure 7 the only resistor that is connected to

the input is the feedback resistor R. As in the

shunt system, R must be made large for lowest noi*e.
Beceuse this noise is white, the total contribution
can be calculated by equ.,ting Af to the equivalent
noise bandwidth of the system. The second *ource of
noise is the current noise from the amplifier input.
This component is essentially the shot noise asaoci­ared with the gate leakage current (io) of the input
device. Its rms value equals . . .

2 x 10-9 F,

With this value the following

F

In this derivation it has been

Eq. 5

FIGURE 6.

0471

LOG FREWENCY

FO

ny tailoring the frequency response of the
amplifier (Pig. 6a) the frequency response
of the shunt method c*n be extended.

F>

FIGURE 6b.

FO

Extended frequency response.

LOG FREQUENCY

F,

OPERATION

MODEL 427

T;; = J-zTp-

where e is the electronic charge. The contribution

of this noise generator is also white. N*t only do

these two noise sources generate white current noise,
the noise in a given bandwidth is also independent

of the input capecitence C. The mejor source of

noise in e feedback current meesurement is the noise

contribution aseocisted with the voltage noise of

the input amplifier. The voltage noise ten be rep-

resented by a VOltage noise generator (0,) et the
emplifier input es shown in Figure 8. This wise
generator itself is assumed to be white. However,
its total noise contribution to the current-measuring

system is not white.

reveal that et low frequencies P large em*u*t of feed­beck ie applied around the voltage noise source {en).

However, the SC combination ettenuetes the high-

frequency components of V,,t so that no feedback is
present et high frequencies. Thus, the noise con-

tribution to the output voltage V,,t from the valt­age noise source a* is no longer independent of

frequency. The noise is “colored” and increases in
intensity for ell frequencies higher than F,. The
resulting noise spectrum is shown in Figure 9b. The
tote1 system noise is related to the are* under
this curve.
plotted on the horizontal axis, the eree under the

curve et higher frequencies represents e signifi­cantly larger amount of noise then e similar eree

*t low frequencies.
the frequency response of the current measuring
system.

interesting et this point to compare this noise
spectrum with the frequency response of the voltage
amplifier in Figure 4 es shown in Figure 6a. A volt­age noise eouec.e et the input of the amplifier would
generate a noise spectrum according to the amplifier

frequency response as shown in Figure 6a. The noise

spectrum of such e system, then, is identical to the

noise spectrum of the feedback system as given in

Figure 9h.

that signal-to-noise performance of a measurement
cen**t be improved by feedback techniques. At the

high-frequency end the voltege noise is limited by

the frequency FA which is the high-frequency roll-

off point of the operational amplifier. It should

Because the logarithm of frequency is

Figure 9e ia identical to Figure 6b. It is

This illustrates the well-known fact

Inspection of Figure 6 will

For comparison, Figure 9a show

he noted that even though the useful bandwidth of

the system extends only t* Fl, there era noise com-

ponents of higher frequency present. To obtain
best widebend-noise performance, these high-frequency
noise components have to be removed. This ca* be

achieved by adding a low-pass filter section follow-

ing the feedback input stage. If the band-pass of

thin low-pass filter is made adjuetable this filter
can nerve the dual purpose of removing high-frequency

noise end of limiting the signal bandwidth of the

system.

2-2. THEORY OF OPERATION.

8. Current Feedback Technique. The basic circuit
configuration used in the current-feedback technique
is shown in Figure 7.
current-measuring resistor R is placed in the feedback
loop of e* inverting emplifier with a gain of A*. The
frequency response obtained with this circuit is iden­tical to thet s+nvn in Figure 6b. F* agein is the
frequency associated with the RC time constant:

F, =

The frequency response of the syetem is extended t* a

frequency fl where

F

, = AoF,

Note that the frequency rerponse is automatically flat
without heving to match break points. However, the
total bandwidth of the system (Fl) is still limited
by the value of the ahunt capacitance C across the

input.
back technique avoids the use of low values for R
which could generate exceesive current noise.

difficulty of the feedback system ariees from shunt
capacitence esaociated with the high-megohm resiaeor R

in the feedheck path.

the resistor is CFr then the bandwidth (FF) of the

system is determined by the time COnstent RCF:

This improved frequency response of the feed-

b. Refinements of the Feedback System. A major

In this configuration the

SE Eq. 6

Eq. 7

.

If the shunt cepacitence acroes

FIGURE 7.

6

Beslc circuit configuration for the feed­back method.

FIGURE 8.

The voltage noise associeted with the am­plifier input device is en important eourc~

of noise in the high-speed feedback syatew

0471

MODEL 427 OPERATION

FIGURE 9.

FIGURE 9b.

The bendwidth of the high-speed feedback

system (Fig. 9a) ten he limited by using
e filter with either e -6 dB/actave or a

-12 dB/octave roll-off. The effect of the
filter on the noise spectrum is showwin
Fig. 9h.

Effect of input capacitance on

noise is shown in Fig..9c.

Effect of filter on noise spectrum.

FIGURE 10.

Frequency compensation.

FF = 1

2 nllcp

Eq.

A slight modification of the feedback loop can correct

this problem es shown in Figure 10. If the time con­stant RlCl is made equal to the time constent R.CF,
it CB* be shown that the circuit within the dotted
line behaves exactly es a resistance R. The matching

of time constants in this cese does not become e draw­beck because the copscitances involved era all constant
and not effected by input impedance.

C. -12 dB/actave Filter.

1. Theory. To obtain optimum widehand noise per-

fomence e filter with e single high-frequency roll­off (i.e.,
dB/octeve is required.

-6 dB/octave) is not sufficient end -12
The effect of e -6 dB filter

is shown in Figure 9a end h. The filter is used to
limit the system bandwidth to a frequency F2, smaller
then Fl. The effect af this filter on the noise
spectrum is shown in Figure 9b. It ten be seen that

there ace egain high-frequency noise components above
F2, the useable bandwidth of the system. These can
he eliminated by using e filter with e -12 dB/octave

roll-off. The result of such .a filter on noise per-

formance is also shown in Figure 9b.

FIGURE 9c.

0471

Effect of input capacitance on noise.

2. Model 427. The input smplifier 18 followed by

en adjustable low-pass filter having e -12 dB/octeve

roll-off end a valtage gain of 10X. The voltage

gain in the low-pass filter avoids premature over-

loading in the input amplifier which ten be seen es
fallows. The maximum output voltage V,,t is $10

volts.

The maximum signal level et the input of the

low-pass filter is, therefore, +l volt. At this
point in the circuit, wide-band noise could still be
present end exceed the l-Volt signal level. The
voltege gain of 10 in the filter allows the total
pre-filter wide-hand noise to exceed the full scale

signal by e factor of 10 (20 dB). The frequency re-

sponse of this filter is edjustahle for variable

“damping” control.

7

OPERATION

2-3.

CONNECTIONS,

MODEL 427

2-5. OPERATING CONSIDERATIONS.

8.

Input.
type which metes with coaxial cables such es Keithley
Models 8201 end 8202.
high.

(5102 on the front, 5103 on the reer panel). These
era BNC type* where the inner contact is output high
end the outer shell is chassis ground.

rear panel is a 3-prong connector which metes with
Keithley pare number CO-6 line cord.

2-4. CONTROLS.

The outer shell is low or chassis ground.

b. Output.

C.

Power Input. The power receptacle (P305) on the

a. Front Panel.

1. Power Switch “PUSH ON” (5302). This switch

controls the line power to the instrument. ‘The

switch is a special pushbutton type with “Power On”
indicated by a self-contsined pilot lamp.

2. GAIN (VOLTS PER AMPERE) (S201). This switch
sets the overall gain in eight positions from 104
to loll.

ment of zero offsets.

3. RISE TIME Switch (5101). This switch sets

the lo-90% rise time in 10 positions from .Ol to
300 milliseconds(for the filter section only).

4. SUPPRESSION (MAX) Switch (S303). This switch

sets the maximum current suppression in eight pasi­tions from lo-10 to 10-3 A. When the switch
to “OFF” the current suppression circuit is disabled.

5. SUPPRESSION (FINE) control (~333). This con-

trol permits adjustment of suppression with 0.1%
resolution.

6. SUPPRESSION (POLARITY) Switch (S304). This

switch set* the polarity of the current suppression

(referred to the input).

7. ZERO ADJUST Control (R235). This control per-

mits adjustment of zero offset through the u*e of the
OVERLOAD indicator.

b. Rear Panel.

1. Line Voltage Switch (S301). Sets instrument

for either 117 or 234 V operation.

The input receptacle (5202) is e SNC

The inner contact is circuit

Two outp,ut receptacles *re provided

A “ZERO CHECK” position permits adjust-

Fuse RequirP.ment* 3AG, Sla-Slo

117V: 1/4A
234V: l/SA

Keithley No. F”17
Keithley No. F”-20

is

set

8. Gain. The gein of the Model 427 is defined in
terms of volts per *“pare. Since the output level is
10 volts for e full scale input, the gain could also

be expressed e* sensitivity in emperes referred to the

input BS in Table 2-1. Vout = - (Iin x GAIN)

Gain or Sensitivity Referred to the Input

GAIN

Setting Resistor

b. Rise Time. The rise time for each gain setting

is listed in the specifications a* “FAST RISE TIME”.

These rise times are obtained when the RISE TIME

switch is set to the positions indicated in Table 2-2.

GAIN

Setti”g

104
105
106
107

1 10;

1oy
1010
loll

c. Suppressian. Current suppression is provided in

the Model 427 for suppression of input currents up to

10e3 amperes.

variations in e larger signal can be observed. Currents

of either polarity can be suppressed. To suppress an
input current the SUPPRESSION should be *et to supply

e current of apposite polarity. The FINE control permits

adjustment up to 1.5 times the MAX setting.

d. Overloads,
en overload et two places in the circuit: before end
after the “RISE TIME” filter circuit. The OVERmAD

lamp (DS302) will indicate whenever the voltsge sensed
ia greater then full scale regardless of the RISE TIME

setting or the frequency.

a. Zero Adjust. The ZERO CHECK po*ition grounds the
the input of the instrument and co”“ert* the cuerent
amplifier to a high-gain voltage amplifier. The ampli-

fied offset voltage will turn on the OVERLOAD indicator
whenever the input voltage offset exceeds 5100 t0l.
Therefore the ZERO control should be adjusted so that

the OVERLOAD indicator is off when in ZERO CHECK mode,

yielding the specified input voltage drop.

Feedback

Switch Settings for “FAST RISE TIME”

Rise
Time

15 ps
15 us

15 I*8
40 us

60 ps .03 ms 800
220
400

1.5 1 ms 100

TABLE 2-l.

Full Scale
sensitivity Output

(Amperes)

103
104
105
106
107
108
109
1010

&Is

“S ps

By suppressing background currents, smell

The overload sensing circuit detects

1

x 10-3
1 x 10-4
1 x 10-5
I x 10-6
1 x 10‘7
1 x 10-g
1

x 10-9
1 x 10-10

TABLE 2-2.

RISE TIME
Setti”g*

.Ol “S
.Ol ms
.Ol “S
.03 “9

.l “S 400
.3 ms 200

Eq. 9

Full Scale

(Volts)

10
10
10
10
10
10
10
10

DYlWl”iC
Range

2000
2000

2000
2000

J

8

MODEL 427

APPLIChTIONS

SECTION 3. APPLICATIONS

3-1. CURRENT~MEASURING SYSTEM. The typical current
meaeuring system consists of a current source, a cur­rent amplifier, and a monitoring device, The current
source could include an ion chamber, photomultiplier,
or other high-impedance device,
such as the Model 427 provides sufficient gain to drive
a monitoring device such as a chart recorder or other
readout. The Model 427 in this case provides an out­put voltage which is calibrated in volts per ampere
a.3 in equation 10.

- (V,,t I GAIN)

Example :

3-2.
trates the trade-off between fast rise time and dynamic
range.
a.s the ratio of maximum peak-to-peak current to peak­to-peak current noise.
taken as 5-times the rms current noise. The maximum
peak-to-peak current is 2-times the maximum full scale
current.

When using current suppression the current-suppres-

sion resistor should be considered as an additional
current-noise generator. The values given in Table
3-l do not include the contribution of the suppres­sion resistor. Therefore the selected suppression
resistor Rs, should be as large as possible to min-

imize the contribution to current noise.

Iin =

GAIN = 106 voltslampe~e
” O”t = +500 In”
The input current Iin would be:
lin = - (5x10-~vo1ts/106vo1ts per ampere)
Iin = - 5 x 10-7

NOISE BANDWIDTH CONSIDERATIONS.

For this application dynamic range is defined

Peak-to-peak current noise is

NOTE

The current amplifier

Eq. 10

amperes

Table 3-l illus-

3-3. NOISE-IMPROVEMENT CONTOURS. The sensitivity
and speed of the Model 427 (for either d-c or a-c

measurements) can be compared to the best perfarm-

ante obtainable with the shunt method of measuring
current. The best “noise-risetime” product that
can be achieved for d-c measurements (with 100 pF
shunt capacitance) in a shunt system is 7 x lo-15
ampere-seconds.
2 x lo-l5 ampere-seconds (also with 100 pF shunt
capacitance).

(lock-in, etc.) the-degree of improvement is a func-

tion of shunt capacitance and operating frequency.

The achieveable imprownene over the shunt method

can be plotted in a graph similar to a set of noise

contours. Figure 11 shows the measured impravemene

(negative dB) that can be obtained with the Model

427 at a given frequency and shunt capacitance when

compared to an ideal (noiseless) amplifier Fn a shunt

system.

,

I

FIGURE 11. Plot of noise-improvement contours.

However the feedback system achieves

When used in a-c narrowband systems

FREOUENCY IHI1

RMS’Noise Current (Typical)1 as a Function of Gain and Rise-Time Setting

TABLE 3-l.

,vL.. I,.,“,.,

PULL SCALE

GAIN
VIA

104
105
106
107

108

109
1010
1011

1

With up to 100 pP input shunt capacitance.

KEY :

x = Filter Bandwidth is greater than current-amplifier bandwidth.
* = larger Rise Times are useful for increased filtering of the signal arid noise inherent in the source.

0471

CURRENT

AMPERES 300 100 30

10-3
10-4
10-5
m-6

10-7

104’

10-9

lo-1o *

They do not further improve the instrument noise contribution except when the input shunt capacitance
exceeds 100 DF.

* * * *
*

* * *
:

*

2x10-15 4x10-15 1x10-14 4x10-14 1x10-13 4x10-13 x

*
* *

*

1x1:-14

*

*

*x1:-14

Noise increases aa input shunt capacitance increases.

RISE TIME SETTING

10 3 1 .3

*
* * *
* *
* *
*

2do-13 2d0-13 5do-13 2~0-12 5x10-12 x x
5~0-14 2do-13 ~0-13 2do-12 x

MO-12 2x10-l2 5x10-12 1x10-11

lx&

*

1x10-8
1x10-9 1.2x10-9 4x10-9
1x10-10

1.5x10-11

.l .03 .Ol

1.2x10-8 4x10-8 1x10-7

1.2x10-10 4x10-10 1x10-9

2x10-11 1x10-10 x

4x10-11

x

x x
x x

1x10-B

x

9

ACCESSORIES

MODEL 427

SECTION 4.

4-l. GENERAL.
be used with the Model 427 eo provide additional con­venience and versatility.

Description:
The Model 1007 is a dual rack mounting kit with over-

all dimensions 3-l/2 in. (64 mm) high and 19 in. (483
mm) wide.
of two Angle Brackets, one Mounting Clamp, and extra
mounting BCreWS.

The following Keithley accesaaries can

Model 1007 Rack Mounring hit

The hardware included in this kit consists

ACCESSORIES

OPERATING INSTRUCTIONS. A separate Instruction

4-2.

Manual is supplied with each accessory giving complete

operating information.

Application:
The Model 1007 co""erts any half-rack, style "M"

instrument from bench mounting to rack mounting in
a standard 19-inch rack.
for rack mounting 19-inch full rack width insfru-

ltE"tS.
The Model 1007 Rack Mounting Kit can be used to m"u"t

instruments of 11 inch or 14 inch depth.
should decide the position af the i"~tr"me"ts to be

rack mounted.

instruments positioned as shown and identified as
instrument “A” and "B".

The Assembly Inaeructions refer co

The kit may also be used

The user

10

Parts List:
Item

NO.

DWCl+ltiO”
22 Angle Bracket
23 Screw, 16-32 x

Phillips Pa" Hd
24 Mounting Clamp
25 Screw, %6-32 x

Phillips Pa" Hd
26 Kep Nut 116-32

27 Screw, 116-32 X

Phillips Pa" Hd

28 Screw, 116-32 x

Phillips Pa" Hd

5/8,

1,

l/2,

718,

VY

Keq'd

2
6

1 247988
1

3

2

1

Keithley
Part No.

27410B

-_

__

_-

__

__

0877

MODEL 427

Assembly Instructions:

ACCESSORIES

Model 1007 Dual Rack MountinS Kit

1. Before assembling the rack kit, determine the

pasition of each instrwnent. Since the inserumenfs
can be mounted in either location, their position
should be determined by the user’s meas”rement. The

following instructions refer to instruments “n” and

UB”

positio”ed as shorvn. For mounfinS 19-inch full

rack Width instruments, disregard steps 2 through 5.

2. Once the position of each instrument has been
determined, ebe “side dress” panels on both sides of
each instrument should be removed. Renxwal is
accomplished by looseninS the screwy (Item 8, oriS­inal hardware) in two places. Slide the “side dress”
panels co the rear of the instrument to remove.

3. The mountinS clamp is installed on instrument
“A” using the oriSina1 hardware (Item 8). With the
screws removed, insert the “mounting clamp” behind
the “corner bracket” (Item 7) and replace the screws
to hold the mounting clamp in place.

4. Tighten the screwy (Item 8) on instrument “B”.

Insert the “mounting clamp” behind the “corner

bracket” (Item 7) an instrument “8” a8 shown.

5. When mounting instruments having the same depth,
a screw (Item 25) and kep nut (Item 26) are required
to secure the two instruments together. When ,,,oune­ing instruments of different depth, da not use kep

nut (Item 26) but substitute shorter screw (Item 28).

6. Attach an “anSle bracket” (Item 22) on each
instrument using hardware (Item 23) in place of the
original hardware (Item 8). For 14 in. long instru-

ments use 116-32 x 518 Phillips screw (Item 23) with

116-32 kep “uf (Item 26).

7. The bottom cover feet and tilt bail assemblies

may be removed if necessary.

8. The original hardware, side dress panels, feet
and tilt bail assemblies should be retained for fut-

ure conversion back to bench mountine.

0777

11

CIRCUIT DESCRIPTION

MODEL 427

SECTION 6. CIRCUIT DESCRIPTION

5-1.

GENERAL.

beck amplifier, e X10 gain filter section, suppression
.“d power supply circuits ee show” in Figure 12. The

feedback emplifier is located an the “Amplifier Beerd”,
PC-289.

Board”, PC-291, PC-292.

located on the “Mother Board”, PC-290. justment. Resistor R307 serves as a current limit de-

5-2.
fier is composed of e high-gain amplifier connected ee
e feedback emmeter.
R227 are set by the GAIN Switch (SZOl). The high-gain
emplffier is composed of a dual FET input stage (Q20IA
end B), e differential amplifier (QAZOl), end en output
stage (9203 end Q204).
resistor R201 to the cutput stage et Q203 end Q204.
Potentiometers R232, R233, and R234 ere internal fre­quency compensetion controls for leg, lOlo, end 1011
gains respectively.

AD., cantrol.

emplifier is 1 volt.

5-3.
of e high-gain amplifier connected aa e 12 dB/octave

low pass filter es sham in Figure 13. The amplifier

consists of intel(rated circuit QAlOl end ~“tp”t stege

(QlOl end Q102).­The gain is established et X10 by resistors RllO end
R112 + R113.
adjustment.

adjustment.

The filter circuitry is located on the “Pilter

FEEDBACK AMPLIFIER (PC-289). The feedback empli-

PILTBR (PC-292).

The Made1 427 is composed of a feed-

The power supply circuitry is alit. Potentiometer R304 is a” internal voltage ed-

The feedbeck resietors R22o through

The feedback is connected from

Potentiometer R235 is the ZBRO

The full scale output of the feedback

The filter circuit ie composed

Full scale output ie 10 ;olts. -

Potentilnwtel: RlOS is en internal zero

Potentiometer R113 is en interns1 gain

a. +15 ” Reguletor.

secondary of transformer T301. The ec ia rectified by

P full-weve bridge rectifier (D301). Trensistor Q301

is the series pees reguletor. Integrated circuit

301 is . self-conteined reference end regulating cir-

vice.

b. -15 ” Regulator.

secondary of trenaformer T301. The ec is rectified by

P full-wave bridge rectifier (D302). Trensietee Q302

is the series pees reguletor.
302 is e self-contained reference end regulating cir-

cuit. Potentiometer R309 is en internal voltage ad-

,ustment.

vice.

5-5.

suppression is applied et the input es show” in Figure

15.
suppression in decade steps from lo-3 te lo-lo *Slp.3=.3*

(Resistors R325 through R332). Potentiometer R333 is

the FINE Control which provides adjustment frnn 0 to

1.5 times the WAX setting. Switch S304 eete the pol­arity (either + end - 15 volt eource). Current sup­presaionis e function of V,,&S,

where “cS = Voltage et the wiper of R333.

Exemple: If MAX AMPEP.Rs = 10-b

Resistor R307 mrves as a current limit de-

CURRKNT SUPPRESSION CIRCUITRY (PC-290). The

The N&X AMPERES Switch (5303) sets the current

IQS = Series Resistor (R325 through R332).

AC power ia tapped from one

QA

AC power is tapped from one

Integrated circuit QA-

--

POWER S"PPLY (E-290).

5-4.

+15 V dc et up to 70 mA for the amplifier circuits.

The regulator circuits ere composed of identicel cam­ponents end are connected ee shown in Figure 14.

The pewer supply provides

GAIN

III

r-5

I I

2!5

SUPPRESSION

FIGURE 12. Block die‘rr of l hi‘h-‘peed current l mplifier

12

end if “cS = cl5 ”

the* Its = +15v = +1.5 x 10-G amperes

107n

RISE TIME

FILTER

0471

Cl01

I,

RIOI

r--------1

0

RI16

0471

FIGURE 16.

component Layout - PC-291.

13

COMI

14

1

FIGURE 17.

Component Layout - PC-290.

MODEL 427

COMPONENT LAYOUTS

?

FTGURE 18.

component Layout - PC-289.

FIGURE 19.

component Layout - PC-292.

0471

15

COMFUNENT L4YOoTS

MODEL 427

PC-290

16

FIGURE 20.

Chaaais - Top View.

0471

MODEL 427

SECTION 6.

REPLACEABLE PARTS LIST: This section contains

6-l.

a list of components used in this instr"ment for user
reference.
individual parts giving Circuit Designation, Descrip­tion, Suggested Manufacturer (Code Number), Manufac-

A
Cb"ar

cem
cefr* Ceramic Tubular
Cer Trimmer ceramic Trin!mer
camp Composition

DCb
twsig.

EAL
ETB
ETT

The Replaceable Parts List describes the applicable. The complete name and address of each

Abbreviations and Symbols

ampere
Carbon Variable

ceramic Disc

Deposited Carbon

Designation

Electrolytic, Aluminum
Elecrrolytic, Tubular

Electrolytic, Tantalum

REPLACEABLE PARTS

F
Fig

GCb
k

I-I

M
Mfr.
MeF Metal Film

MY
NO.

turer's Part Number, and the Keithley Part Number
Also included is a Figure Reference Number where

Manufacturer is listed in the CODE-TO-NAME Listing

following the parts list.

TABLE 6-l.

farad n ohm
Figure

Glass enclosed Carbon Printed Circuit

kilo (103)
micro
~~~ (106)

Manufacturer
Mylar w watt
Number

(10-6)

&

P0ly Polystyrene
Ref.
TCU
v volt

w/l
WW"ar

pica (10-12)

Keference
Tinner Copperweld

WiR?WO"nd
Wirewound Variable

6-2. ELECTRICAL SCHEMATICS AND DIAGRAMS. Schematics
and diagrams are included to describe the electrical
circuits as discussed in Section 5. Table 6-2 idenc-

ifies all schematic part numbers included.

HOW TO USE THE REPLACEABLE PARTS LIST. This

6-3.
Parts List is arranged such that the individual types
of components are listed in alphabetical order. Main

Chassis parts are listed followed by printed circuit
boards and other subassemblies.

NOW TO ORDER PARTS.

6-4.

a. Replaceable parts may be ordered through the

Electrical Schematics and Diagrams

Description Schematic

Amplifier iloard
Mother Board (Power Supply)
Filter Board

TABLE 6-2.

Sales Service Department, Keithley Instruments, Inc.
or your nearest Keithley representative.

b. When ordering parts, include the following in-

formation.

1. Instrument Model Number

2. Instrument Serial Number

3. Part Description

4. Schematic Circuit Designation

5. Keirhley Part Number

C, All parts listed are maintained in Keithley
Spare Parts Stock. Any part not listed can be made
available upon request. Parts identified by the

Keitbley Manufacturing Code Number 80164 should be

ordered directly from Keithley Instruments, Inc.

I

PC-289 247660
PC-290 247680

PC-291, PC-292 247671)

0471

17

REPLACEABLE PARTS

MODEL 627

TABLE 6-3.

PC Board Designation series

I

Itern NO.

10
11

12
13

14

15

16
17
18
19

20

1

100 Filter Circuit

100 Filter Circuit
200 Amplifier
300 Power Supply
300 SuppressFan circuit
300 Overload Circuit

Chassis Assembly

Front Panel Assembly
1
2

3
4
5
6

7
8
9

\

Front Panel

Screw, Slotted, 6-32 x 318

Front Panel Overlay
Rear Panel
Side Exerusion Left
Side Extrusion Right
corner Bracket
Screw, Socket, 6-32 x 114
Screw, Phillips, 6-32 x l/4
Clip for Side Dress
Side Dress Panel

Tap Cover Assembly

Top CO"er
Screw, Socket, 6-32 x 5116

Bottom Cover Assembly 24763B

Bottom cover
Screw, Socket, 6-32 x 5/16
Feet Assembly

Feet

Ball

Tilt Bail

Screw, Phillips, 6-32

Kep Nut, 6-32

f,k -\U'&

TABLE 6-4.

Mechanical Parts Lise

Qty. Per Assembly Keithley Part No. Figure NC

PC-291
PC-292
PC-289
PC-290
PC-290
PC-290

1
4

1
1

1
1
2
4
4
2
2

1
4

1
4

4
4

1
4
4

247566
24758B

247608
24754C
24754C
247458

FA-101
24755B

24732C

2473X

243228
FE-6
171478

20
20
21

23
23
23

21

22

18

WARNING

Using a Line Power Cord other than the one suppLied

with your

shock hazard.
damaged, replace only

instrument

If the Line Power cord is lost or

may result in an electrical

with

Keithley Part No. CO-7.

0878

MODEL 427

REPLACEABLE PARTS

0471

FIGURE 21. Chassis Assembly-Exploded View.

FIGURE 22.

Bottom Cover Assemblv.

REPLACEABLE PARTS

HOOEL 427

circuit
Ilesig. Value

Cl01

Cl02 680 ;i
Cl03
Cl04 6800 pF
Cl05 .022 @

Cl06
Cl07
Cl08
c109*
c110*

Cl11
Cl12

c115*

Cl16 .033
Cl17
Cl18 .33
c119s 1
c120* 3.3

150 oF

.0022 p

.068 uF

.22

'b

.68 p

2.2 pP

6.8 @
68 pF

330 DF

.Ol

.l

Rating

-

500 v
500 "
500 v
500 v
200 "

100 " MY
200 v MY
200 v MY
200 v MY
200 v MY

500 v P0ly
500 v Poly
500 " Poly
500 " Poly
200 " Poly

100 v MY
200 v MY
200 v MY
200 " MY

200 v

\

("100" SERIES, PC-291*, PC-292)

P0ly
Poly
Poly
POlY
Poly

MY

FILTER BOARD

CAPACITORS

Mfr. Mfr.
Code msig.

71590
71590
71590
71590
84171

88480
13050
13050
13050
97419

71590

71590 CPR-330.1
71590

71590
84171

88480

13050

13050

13050

13050

CPR-15OJ
CPR-68OJ
CPR-22OOJ,
CPR-68OOJ
2PJ-223G

~FR-683-1E
WA-.22j,F
SMlA-.68,,F
SMlA-2.2,,F
M2WF-6.LQF

CPR-68J
CPR-1OOOJ

CPR-3300J
2PJ-10x

3FR-333-1E
SMlA-.lPF
SMlA-.33pF
SMlA-1pF
SMlA-3.3,~F

Keithley Fig.

Pat-e No. Ref.

C138-15OP
C138-68OP 19
C138-.0022M 19
C138-68OOP 19
C108-.022M 19

C146-.068M 19
C47-.22M
C47-.68M
C47-2.m
C203-6.&I

C138-68P 19
C138-33OP 19
C138-.OOlM 19
C138-.0033M 19
C108-.OlM 16

C146-.033M 19
C47-.lM
C47-.33M 19
C47-1M
C47-3.3M

19

19
19

16
16

19
16

16

Cl21 5
Cl22 5
Cl23 33
Cl24 100

CiX”it
”

“C3l.g.

no1 connector, lo-Pin, Mini-w

QAlOl Integrated Circuit

0101 Diode, Rectifier

0102 Diode, Rectifier
QlOl Transistor
Q102 Transistor

SlOl Switch, Rotary, RISE TIME

5102 Connector, BNC, UG1094A/U
_- Cap, BNC, mates with 5102

Value Rating

RlOl 7.78 kn I%, l/8 w

R102 8.41 kn l%, l/8 W

R103 51.7 kn l%, l/8 w
RlO4 51.7 kR 1%, l/8 w
R105 10 kn l%, l/8 w

1000 " CerIl
1000 " CerD
1000 " CerD
100 " &lZIl

Type

Type
MfF

MtF
MtF
MCF
MtF

72982
72982
72982

72982

MISCELLANEOUS

Mfr.

code
22526

12040
01295

01295
04713
04713

80164
02660

RESISTORS

Mfr. Mfr.
Code Desig.

07716
07716
07716
07716
07716

m-050 C64-SF 19
m-050
DD-330
m-101

Mfr.

Lhsig.
20052

LM301AN

lN914

lN914
2N3903
2N3905

SW33S
31-2221

CEA-7.78KG R88-7.78k
CEA-8.41~Jl R88-8.41k

cm-51.7m R88-51.7k
CEA-51.7UJ R88-51.7k
CEA-lO* R88-10k

C64-5P
C64-33P
C64-1OOP 19

Keithley

Part No.

CS-237
IC-24
RF-28
RF-28
TG-49
TG-53

;;r;g
CAP-18

Keiehley
Part No. Ref.

19
19

Fig.

Ref.
19

19
19
19
19
19

19

Fig.

19
19
19
19
19

3

20 1072

FlLTER BOARD (cont'd)

RESISTOR8 (cont'd)

Value
1

R106
RIO,
R108
R109
RllO

Rlll 10%. l/4 w

C203
C204
C205

kfl l%, l/8 w

1

kil

200 n

61.9 kS
2 kn
10 kn
470 !?

1.8 kfl

10 k0
470 R
200 iz

10 kR

RCltF"g Type

1%, 1/B w

75 w
:l%, l/2 w
.l%, 112 w

.l%, l/E w
.75 w

l%, l/8 W
10%, l/4 w

1%, l/8 w
1%. l/8 w
lo%, l/8 W
l%, l/8 W
l%, l/8 W RI20

1000 v
1000 "
600 V

1000 "
200 v

Mfr.,
Code

MtF
MCF
Camp
MCF

MtF

camp

MCF

camp

MtF

camp

MU
MU

camp
MtF
Ml3

‘WPLIFIER BOARD

("200" SERIES, E-289)

CerD 72982
&l-D 72982
&t-T 71590
cem 72982

MY

07716
07716
80294
91637
91637

44655
91637
80294
07716
44655

07716
07716
44655
07716

07716

CAPACITORS ( * Located on Switch S201. )

Mfr.

13050

Mfr. Keithley
Desig. i'art NO.

CF.&-lkn
CEA-lkS2

3009P-200
Km-Ml
MFF-536R

RCO7-102
MFF-61.9kR

3009P-2k
CPA-l.Okn
KC07-471

CEA-1.RkR
CEA-IOkR
RC07-471
CEA-200n
CEA-1Okn

Mfr. Keithley

loss-D22
801000X5F0102~ C64-.OOlM

TCZ-1R5

801000~5~0102~ C64-.ool~
SM2‘+.047IJF

R88-lk 19
R88-lk 19
RP-89-200 19
R169-1M 19
R168-536k 19

R76-lk 19
R168-61.9k 19
K-89-211 19
R88-10k 19
,176.470 19

R88-L.8k 19
R88-1Ok 19

R76-470 19
R88-200 19
R88-IOk 19

C22-.0022M

c77-1.5P
C143-.047M

Fig.
Ref.

Pig.

18
18
18
18
18

C206
C207
C208
C209
c210

.047 p

470 pF

.0022 UF
,001 b

10 ilF

,001 LP 1000 ” 72982

10

iJ.F

.OOl UF

.oo47 ilF*"
.0047 IiF

470 pF
*C217
*C218

C219
c220 cG-5
c221

c222
C223
C224

**Nominal Value, Selected in Factory Test

47 pF

5

PF

1.5 DF

1.5 6F 600 "
,033 pF 100 "
.OOl UF
.0033 !,F
.0033 5

200 "
1000 v

1000 v
1000 ”

20 "

20 v
1000 v

200 v

1.000 v

500 " * C216
500 v
200 v
600 v

1000 "
1000 ”

1000 v

MY

CerD

13050
72982

72982
17554

17554

72982
97419
56289

71590
71590
00686
71590
71590
88480
72982

56289
56289

SMZA-.047PF

00471

loss-"22
801000X5F0102K

TSDl-20-low
801000X5F0102K

TSDI-20-10°F
8omoox5Foio2K C64-.OOlM

loss-D47

TCZ-IRS

3FR333-1E
801000X5F0102~
1oss-033
loss-D33

C143-.047M 18
C64-47OP 18
C22-.0022M 18
C64-.OOlM 18
C179-10M 18

C64-.OOlM 18
C179-LOM 18

C66-.0047M**
C22-.0047M 20

wp c a-~w-r~s,fy
C146-.003M 18
C64-.OOlM 18

C22-.0033M 18

C22-.0033M 18

18
20

1075

21

FiXPLACEABLE PARTS

MODEL 427

AMPLIFIER BOARD (cont'd)

CirCUit
Desig.

D201

0202
D203

D204
D205

D206
D207
D208

D209
D2lO

QA201 wegrated Circuit, Operational Amplifier

s201
5201
5202

Type

Special
Special
Silicon, NPN, case TO-106
Silicon, NPN, case TO-106

SilkOn
Silicon
SiliCOtl
Silicon

Type

Switch, Rotary, GAIN
Not Used
Receptacle, BNC (UG1094AfU)

DIODES

Mfr.

Code
80164

80164
07263
07263

01295

01295
01295
01295
01295
01295

MISCELLANEOUS

Mfr. Mfr. Keithley Fig.

Code tlesig. Pare NO. Ref.

07263
80164

02660

RESISTORS ( * Located on Switch 5201. )

Mfr.
msiu.

.?&5sk

2133565
2N3565
lN645

lN645
lN914
lN914
lN914
lN914

@715C
SW-337

31-2221

Keithley

Part NO. Ref.

-2245&A .2&l\;' (*‘4 18
TG-39

TG-39

RF-14 18
RF-14 18

RF-28 18
RF-28 18
RF-28 18
RF-28 18

IC-26 Jk: ;::c;,d 18
SW-337 ? ,~> 18

cs-249

Fig.

1 S Z2&55A ;> fj 3 :I ,~ c:Jj
18
18

18
18

R201
R202
R203
R204
R205

R206
R207

R208
R209
R210 499 n

R211 499 n
R212 10 R
8213 470 n
R214 10 kn
R215 470 n

R216

R217
* R218 270 kn
* R219
*R220

* R221
"R222
9~ R223

R224
R225 108 n

10 n
1 MCI

100 kR

23.2 k0

22.1 k0
10 ki? l%, 118 W

18.2 kn l%, l/2 w MtF
10 kfi l%, l/S w MtF 07716

12.1 kO l%, l/8 W MtF

10 n
10 D

100 n

900 a

10 kn
100 kR
1 wl
10 MS?

Mfr.
Code Desig. Part No. Ref.

lo%, l/4 w
lo%, l/2 w
I%, l/8 W
l%, l/8 W
ix, 118 w

l%, l/S w MtF 07716
l%, l/8 W

l%, l/S w
lO%, l/4 w
l%, l/S w
IO%, l/4 w

10%. l/4 w
lO%, l/4 w
lO%, l/2 w

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

l%, l/2 w
l%, l/2 w
l%, l/2 w
1%,1 w
1%,2 w

corn;
MtF
MW

MtF
MM 07716

MtF
MtF

COmp '44655
Camp 44655
camp

Mm 07716

DCb 91637

MtF 07716 CEC-1OM

MtF 07716
Mm 07716
DCb 91637
DCb 91637

44655
01121
07716
07716
07716

07716
07716

07716
07716

44655
07716
44655

01121

Mfr.

RC07 R76-10 18
EB-lM
CBA-lOOki? R88-100k
CF,A-23.2kn

CEA-22.lkn
CEA-1OM R88-10k 18

CEC-18.2kQ R94-18.2k 18
CEA-lOkS1 R88-10k
CBA-12.lka R88-12.lk
CEA-4990

CEA-499n
CEA-lOS2
RC07-471
CEA-low2

RC07-471

RC07-100 R76-10 18
RC07-100
EB-270kR
CEC-loon
DCF-l/2-90Ofi

CEC-100kn
CEC-lMn
DC-l-lOM0
DC-2-1oSn

Keitbley Fig.

RI-1M
R88-23.2k 18

R88-22.lk 18

RS8-+,9- 3-01Lc

R88-449
RSS-10

R76-470 18
RSS-10k 18
R76-470 18

R76-10 18
Rl-270k 20
R94-100 20
812-900

R94-10k
R94-100k

301&

18

18

18
:i

18
18

20

20
26

22

1072'

MODEL 427

REPLACEABLE PARTS

AMPLIFIER BOARD (cont'd)

RESISTORS (cont'd)

Value Rating Type

R226
R227
R228
R229
R230 220 kn

R231 330 kfi
R232 100 kR
R233
R234
R235 500 n

h~ominal value, selected in test.

circuit
iksig. Type

Q201
Q202
Q203
Q204

*Selected X-70

109 n GCb
1010 n : GCb

*15 R

10 kn

10%. l/4" camp
10%. 114 w
lo%, l/4 w corn;

lo%, l/4 w

l/2

1 Mn

1

MCI

Dual, PET, case TO-71
Silicon. NPN, Case TO-92

Silicon, NPN, Case TO-92

PNP. Case TO-92

112

,,,,,,,,m;,,. E

112

Mfr. mr* Keiehley
Code Llesig. Part NO.

63060
63060

ComJ

camp

MOTHER BOARD PARTS LIST

("300" SERIES, PC-290)

44655
44655
44655

44655 RC07-334

80294

80294 3068P-Df
80294 3068%1M

llelipot

TRANSISTORS

Mfr. Mfr.
Code

80164 2N5452
04713 2N5089­04713 2N3903
04713

CAPACITORS

Fig.
Ref.

9
g::::;10
x07-150

RC07-103 R76-10k 18
RC07-224

3068P-100k

77PF.500

Lksig. Part No.

2N3905

RZO-109 R*l-rb20
R20-10lC$3~5-,&0
R76-15

X76-220k 18
R76-330k

RP89-10Ok
RP89-lM
RP89-1M

RP-64-500

Keithley

25099.4"
'X-62 18
w-49 18
z-53 18

18

18
18
18
18

Fig.

Ref.
18

Value Rating Type

c301
C302 200 fl
c303
c304
c305

C306
c307
C308
c309
c310

C311
C312
c313
c314
c315

D301 Four Wade Bridge 83701 m-10 RF-36 17
D302 Four Diode Bridge 83701 PD-10 RF-36
D303 Silicon 01295 lN645 RF-14 17

0304 Not Used __ __ __ -­0305 Silicon 01295 lN914 RF-28 17

200 p

10 llF
10 @

2200pF
200 p

200 UF

10 GF

2200PF

10 fl

200 p
10 UF

.47 pE

10 P
O.Ol!JF

35 "
35 v
20 "
20 v

1000 ”

35 "
35 "
20 "
1000 "
20 "

35 "

20 " ETT
20 "
20 "

500 "

EAL
EAL
ETT
ETT
CC?!2D

EAL
EAL
ETT
CerD
ETT

EAL 90201

Mfr.
Code i%sig. Part NO.

90201
90201
17554
17554
72982

90201 MTV-200UF C177-200M
90201 MT"-200!JF C177-200M
17554 TSDl-zo-10UF C179-10M
72982
17554

17554

Mfr.

Mfr. Keiehley

MT”-200m
MT”-ZOO!JF

TSD1-20-10pF
TSDI-zo-IO&IF
m-222

DD-222
TSD~-20-10uF C179-10M

MTV-200m

TSDl-ZO-10pF

Tml-20-.47UF
TSDl-20-lO!JF

871-25u0-103M

C177-ZOOM
C177-200M
C179-10M
C179-10M
C64-2200P

C64-2200~

C177-200M

C179-10M

C179-.47M
C179-10M

C22-.OlM

Keithley

Fig.
Ref.

17
17
17

17
17
17

::

Fig.

17

REPLACEABLE PARTS

MOTHER BOARD (cont'd)

DIODES (cont'd)

MODEL 427

Cit-CUit
rlesig.

D308
0309
D310
0311
0312 Silicon

5301

5307.

QA301

QA302
QA303

5301
S302

5303
Q301

4302
Q303

5304
F301
F301
T301
P305

__
DS-301

DS-302

CirCUFt
Llesig. Rating Type

Type

Silicon
SiliCOll
Silicon

Silicon 01295

Type

Connector, Mini-P"
connector, Mini-P"
Integrated Circuit, Voltage Regulator 07263
Integrated Circuit, Voltage Regulator 07263 LEA7723393 IC-25

Integrated Circuit
Switch, Line Voltage
Switch, "PUSH ON" Power with lamp
Switch, CURRENT SUPPRESS 80164 SW-339 SW-339

Transistor
Transiseor
Transistor,
Switch, POLARITY
Fuse, 117", .25A, Slo-Blo, 3 AG
Fuse, 234", 1/8A, Slo-Ho, 3 AG
Transformer
Receptacle, AC

Line cord, mates with P305
Pilot lamp, neon (replacement far 5302)

Pilot Lamp, O"~RLOAD

Value

Silicon, NPN, TO-92 case

iESISTORS (*Located on Switch S303.)

Mfr.
Code

01295
01295
01295

01295 lN914

MISCELLANEOUS

Mfr. Mfr.
Code

22526 47439
22526 47439

07263 A749C
80164 SW-318
80164

02735 40312
02735 40312

04713
80164 SW-236

75915 313.250
71400 MDL

80164 TR-138
82389 AC3G
70903 17258-S co-7
08806
07294 CF03ACS1869

Mfr.
Code

Mfr.
rJesig.

lN914
lN914
lN914

lN645 RF-14

Desig.

UGA7723393

PBL-5-BSA3C7A SW-340 3

2N3903 TG-49 17

C/A(N&2P) PL-58

Mfr. Keithley

LkSiE. Pat-t NO.

Ketthley
Part No.

RF-28
RF-28
RF-28

RF-28

Keiehley

Part NO.
CS-236

CS-236
IC-25

x-27 17
SW-318 3

TG-54 17
w-54 17

SW-236 3
F"-17 3
F"-20 3
TR-138 20
CS-235 3

PL-51

Fig.
Ref.

17
17
17

17

__

Fig.
Ref.

17
17
17
17

‘20

-_

FFg.

Ref.

2

R301
R302
R303
R304
R305

R306
R307

R308

R309

R310
R311

R312
R313
R314
R315

R316
R317
R318
R319
R320

R321
R322
R323
R324

hR325 10 kn

634 0

8.2 a

1.37 kfi
200 0.

1.24 kfi
634 R

8.2 n

1.37 kn
200 a

1.24 k.Q

9.09 kfl
14 kn
1 kR
10 n
1 kfl

9.09 kR
1 kfl
1 kR
14 kn
10 R

10 kn
10 kfi
330 R
47 kfl

l%, l/8 w
5%, l/2 w
1%, l/8 w

0.5 w

ix, ua w

1%. l/8 W:
5%, l/2 w
l%, l/8 w

0.5
l%, l/8 w

l%, l/8 w
l%, l/S W

W

I%, ifa w

lO%, l/4 w
l%, l/8 w

l%, l/8 "
l%, l/8 w
l%, l/8 w
l%, l/8 W
lO%, l/4 "

COmp
MtF

MtF
MtF

COtlIp
MtF

MtF
MtF

MtF 07716

MtF

CO*p 44655

MtF 07716

MCF
MtF
MtF
MtF

07716 CEA-634n R88-634 17
01121
07716
80294
07716

07716
01121
07716
80294

07716
07716
07716

07716
07716
07716
07716
44655

44655
44655
44655
44655 x07-473 R76-47k
07716

EB-8.2sl

CEA-1.37kn

3329P-200

CEA-l.lkO
CEA-634n

m-8.2$?
CEA-1.37kR
3329P-200
CEA-l.lkR

CEA-9.09kn
CEA-14kfi
CERlkR
RC07-100
CEA-lkn

CEA-9.09kn
CFA-1kR
CBA-1kR
CEA-14kn
a07-100

RC07-103 R76-10k
RC07-103
x07-331

CEC -1Okfl

R19-8.2
R88-1.37k
RP-88-200

Rae-l.24 17
R88-634

R19-8.2
R88-1.371
RP-98-200
~88-1.24

R88-9.09k
R88-14k
R88-lk
R76-10
R88-lk

,R88-9.09k

RBB-lk
R88-lk
R88-14k
R76-10

R76-10k
R76-330

R94-1Ok

17
17
17

17
17
17
17
17

17
17

17

I 17

17
17

17
17
17
17

17
17
17
1Y

20

24

0574

MODEL 427

REPUCEABLE PARTS

MOTHER BOARD (cont'd)

RESISTORS (cont'd)

circuit
lksig.

Value Rating

100 kn

1
10 Mn l%, 1 w DCb
100 MO DCb
109

hR331
*R332

F.333 10 k0
R334

R335

1010 R CCb 63060 Rx-l-101On
1011

33 kn

68 kSI

Mfr.

Type

l%, l/2 " MtF

Mn

n GCb

il GCb 63060 Rx-l-1olln

l%, l/2 w
1%,2 w

2 W ww 12697 62JA-10kiI RP-YZ-10k

lO%, l/2 w

lO%, l/4 w C0mp

MtF

Camp

Code

01121
44655

Mfr.
Desig.

CEOlOOI& R94-look 20
CEOM-i
DC-l-1OMn
DC-2-100Mo
Rx-l-1090

EB-33kn

RC07-683 R76-6Sk

Keithley

Part No.

R94-1M

-to

.rw-dl pw3~-@620

Rl- 33k

f$e~-/“G

Fig.

Ref.

2.

17

17

__

1176

25

SECTION 7. CALIBRATION

MODEL 427

GENERAI..

7-1.
checking the instrument to verify operation within
specifications. The procedures and adjustments should
be performed in the exact sequence given to obtain
satisfactory results.

7-2. TEST EQUIPMENT.
in Table 7-1.

tuced provided the accuracy tolerances are equal to or

better than the equipment specified.

The Suppression Max. Amperes switch will be left
in the E posirion unless stated otherwise.

PKOCED”RES .

7-3.

a. Preliminary Calibration.

1. Power Supplies.

a).

point and chassis and adjust the f15 volt poten-

tiometer R309 for +15 Volts t10 "". "Sing the
oscilloscope check for less than 1 m" peak-to­peak ripple.

b). Connect Model 163 between the -15 volt test

point and chassis and adjust the -15 volt poten-

tiometer R304 for -15 volts ?lO mV. Check for less

than 1 mV peak-to-peak ripple.

This section contains procedurea for

Use the test equipment specified

Equivalent instruments may be substi-

NOTE

Connect Model 163 between the +15 volt test

2. Line Regulation.
Plug the Model 427 line cord in to a "ariac

a).

with Line Monitor.

Check the il5 volt supplies with the "ariac

b).

adjusted for 90 and 125 volts. The voltages should

be i-15V +20 m" with less than 1 mV peak-to-peak

ripple.

3. 234 Volt Operation.
Set the 117-234 volt switch to the 234

a).

volt position and plug the 42, line cord into the

234 volt line.

b). Check the 215 volt supplies. They should

read i15 volts ?1O mV with less than 1 mV peak-

to-peak ripple.

4. Overload Circuit Check.
Connect Model 163 to the Model 427 output.

a) f

Set the Model 163 to the 10 volt range.

Set the Model 427 controls as fallows:

b).

GAlN : 106 "olts/amperes

SUPPRESSION: (-1 10-5 amperes

RlSE TIME: 300 Ins

c). Turn the Suppression Fine control to obtain

a reading of approximately t9.5 V on the Model

163.

The Model 427 overload light should be off.

1nStr”ment Type

I-

Picoampere source
Digital Voltmeter

Oscilloscope
Function Generator
Microvolt-*meter
Variable Transformer
Line Voltage Monitor
True RMS "TVM

26

TABLE 7-l.

Test Equipment

Specification
10-14

to 1.1 x lo-4A

il uv to lOOOV, 0.1% of reading

__

-_

-11

_-

10

to 10-l*

10 "V fO lOOOV,
90-140V rms, 50-60 Hz
90-140V rms, X-60 Hz

Mfr. and Model No.

Keithley, Model 261
Keithley,,,~Model 163
Tektronix, Mod'+,~~ or 5618 ,,~
Wavetek, Model 111 or 130
Keithleiy, Model l?i
variac ',l_

--

Ballantine, Model 320

~/,'

-I

1072

MODEL 427

CALIBRATION

d). Slovly t”rn the Suppression Fine control
CW until the overload light comes on. ~,,is
should occur between +10 and +11 volts.

e). Set the Model 427 Suppression Polarity
switch ta (+) and repeat steps & and c, Readings
on the DVM will now be negative.

5. current Amplifier Zero.

a). Set the Model 427 gain switch to zero check,

suppression to E and Rise Time to 30” ms.

b). Turn the 427 front panel zero control ccw
until overload light comes an. Then very slowly
turn the zero control cw until light goes off.
C”“ti”“e turning c0*tr01 cw until light comes on
again. Then slowly turn control ccw and set in
region where overload light stays off.

6. Filter Amplifier Zero and Gain.

a). Set the Model 427 gain to lo4 V/A and Rise
Time to 300 me. Connect the Model 163 DW to the
Model 427 output. Set the Filter Amplifier zero
pot (F.108) for 0 ilm” at the Model 427 output.

Set the 427 Gain to lo5 V/A and cmmect a

b).
DVM (1V range) to the OUtPUt Of the first stage amp­lifier (QA201, Q203, 4204) at location on PC-290

(mother baard) at jumper found directly below pot-

entiometers R232 and R233.

set the Suppression to

10” amperes and adjust the front mnel pot R333 for

a reading of l.OOOV.

connect DVM (1OV range) CO
output of 427 and adjust Filter Amplifier gain
pot (R113) for a reading of 10.00 volts.

Set the Model 261 to N6 ampere and the

a).

Model 427 gain to 10’ V/A and connect the test

set up as shown in Figure 23 using a BNC TEE

connector on the Model 427 input.

b). With no input connected set up, the Model
153 for CENTER ZERO and VOLT K-21%. Zero on the
100 pV range then set the range to 1. mV.

c). >ir&t$ Model 261 output OFF increase

the -1 153 $ensftivity to 300 v” range while

mai”camCig~ a “0” Indication on the Model 153

using the Model 427 front panel zero control.
Correct drift with the Model 427 zero co”trol as

needed during checks.

d). Switch the Model 261 between OFF and (+)

,..~as\p,eeded to obtain a steady reading on the Model

! 153.’ me reading should be leSS tha

P-

300 pv.,

e). Repeat step $ but witch befw:&,FF~%“d
(-) on tiy Model 261. The reading should be
less thqh +300 u”. Re-zero the Model 427.

0877

FIGURE 23.

Measurement of Input Voltage Drop.

27

CALIBRATION

MODEL 427

TABLE 7-2.

427

GAIN V/A RISE TINE FREQUENCY

11

;;10
109

108
107
106
105
104

8. Amplifier Rise Time.
Connect Function Generator to the Model

a).
427 input and connect the Model 427 rear panel
output t" the Oscilloscope Using the test set up
shar" in Figure 24.

Adjust the 10' through 1011

b).
the specified 10% to 90% rise time using the tri­angular wave frequency and adjustment listed in
the table. Adlust the Function Generator as

needed to obtain a 10 volt peak-to-peak output

from the Model 427.

rangea for the specified rise times. There should
be no overshoot on any of the ranges.

Check the 10 through lOti

427 WAVETEK

1.0 ms 100 Hz
.3 me 500 Hz
.l ma

.03 ma 2 kHz
.03 me 10 kHz
.Ol m 10 kliz
.Ol me 10 kH*
.Ol r@E 10 kliz

ranges within

1 kHz

MAX 10-90x

RISE TIME

1.50 "Is Slider 6 Pot

0.40 m

0.22 la8 Pot

0.60 me None

0.40 me

0.015 Ins NO"=

0.015 ms Ncme

0.015 ms NO"=

9. Amplifier Noise.

a) .

427 input high end ground.

rear panel output and check the Model 427 BMS
output noise for all settings in Table 7~3.

10. Filter Rise Time.

Connect B 1OOpF capacitor between Model

Connect the TRMS VTVM to the Model 427

b).

Set the oscilloscope controls as follows:

4.
VERTICAL INPUT: ZV/Di".

COUPLING: DC'
TRIGGER:
COGPLING: AC

Ext.

RISE TIME

ADJUSTMENT

Slider 6 pot

NO"=

Shielded

/

- r ,I,,,1
PUNCTION
GENERATOR

- L-- J

GAIN V/A

(427)

11

;;10
109

1oS
107
106
105
104

i

, CAPA

_ I

I ,

FIGURE 24. Measurement of Rise Time,

TABLE 7-3.

RISE TIME

(427) T

1.0 ms
.3 In*

.l ms
.03 me
.03 me

.Ol ma
.Ol ma
.Ol m

TRUE
MS

100

"I"
30 mv
10 mv
10 mv

3 mv
3 mv
3 mv
3 rev 2 mv

I I

MAX. RMS

NOISE

40 mv
20 mv
10 mv

5 mv

2 nlv
2 mv
2 mv

28

0574

>

MODEL 427

CALIBRATION

TABLE 7-4.

10 !a
10 pa

.l Ins
.l nla

1 ms
1 me

10 me

1.0 tn.5

FUNCTION
GENERATOR

Wavetek

Frequency

10 kHz .Ol Ins .015 In*

1 kHz .03 me .040 me

1 kHz .l In* .15 ms
100 HZ .3 me .37 ma
100 Hz 1 me 1.1 Ins

10 H7. 3 Ins 3.7 Ins

10 "7. 10 Ills 11 m

10 HZ 30 Ilie 37 me

SERIES

RESISTOR MODEL 427

1om

FIGURE 25. Measurement of Filter Rise Time.

427 Rise Time

setting

CURRENT

AMPLIFIER

Max lo-90%

OSCILLOSCOPE

RfSe Time

Set the Model 427 gain to lo4 V/A.

b).

the series resistor (104) and the square wave fre­quency listed, check the filter amplifier lo-90%
rise time.
as needed to obtain a 10 volt peak-to-peak ""tput
from the Model 427.
a combination of both should not exceed t 10%.
Trigger the Oscilloscope from the Function Gen­erator sync output.

Set the Function Generator amplitude

The overshoot and dipping or

“*“etek

OSCillO*COpe

.l eec 1 HZ 100 me 110 Ins
.l set 1 HZ

Frequency Setting Rise Time

L

"sing

TABLE 7-5.

the Function Generator for 1 volt out of the
Model 427.
below check the lo%-90% rise time of the filter

amplifier.

427 Rise Time Max lo-90%

300 tns 370 Ills

"sing the square wave frequency listed

Set the Oscilloscope for .2V/Div and set

c) .

0574

29

CALIBRATION

MODEL 427

b. Final Calibration.

1. Gain Accuracy.
Connect the Model 261 Picoampere Source to

4.
the input of the Model 427 and connect the Model
163 to the Model 427 output.

Tima Co"sta"t to 300 Ins.

Set the Model 163 on the 1 volt range and

b).

step the Model 261 and Model 427 through the ranges
in Table 7-6.
range given.
age OUtpUt is negative.

261

-

2. Offset current 4. Drift.

The DVM readings must be within the

For positive current inputs the volt-

TABLE 7-6.

427 Gain

Set the Model 427

Model 163

.98V to 1.02V
.98V to 1.02v
.98V to 1.02v
.98V to 1.02V
.98V to 1.02V
.98V to 1.02V
.96V to 1.04V
.96V to 1.04V

4.

through the positions in Table 7-7. The readings

on the Model 163 should be within the tolerance

polarity switch in the (-) position. The Model

163 readings will now be positive.

Step the Suppression and Cain switches

TABLE 7-7.

SUPPRESSION

LO-lo
10-9
10-8
lo-7
lo-6
10-z

IO-3
10

Repeat stepa a and c with the suppression

d)

-lov t10 mv

-lOV -i600 mV

-lOV i-600 mV

-10" i600 mV

-lOV t600 mV

-lOV f600 mV

-lOV C600 mV

-lov i-3 "

MODEL 163

Re-check the current amplifier and filter

a).

amplifier zero. Place a CAP-18 on the Model 427

input and sat the Model 427 Cain to 1011 V/A and

Rise Tim2 to 300 ma.

b). Connect the Model 163 to the Model 427 out-

put and set it to the 1 volt range. The reading

on the Model 163 should be less than 100 mV.

3. current suppression.
a). Place a CAP-18 an the Model 427 input and

set the gain to lo11 V/A. Connect Model 163 to

the Model 427 output and set it to the 10 volt
range.

Set the Model 427 Suppression switch to

b/6

lo- , set the Polarity to (+) and the Fine co"­tral to obtain a -10 volt i10 m" reading on the

Model 163.

Set the Model 427 controls as follows:

4.
GAIN: LO5 V/A

SUPPRESSION: 1O-7 ampere

RISE TINE: 1 ms

POLARITY:
*POLARITY is (+) for setting recorder

printer left of zero and (-) for setting
printer right of zero.

Set the recorder sensitivity to 10 mV full

b).

scale and "sing the suppression FINE control set
the recorder printer to a convenient spot for

recording drift of the Model 427.

After a 1 hour warm-up the Model 427

c) .

should drift no more than t500 u" (five minor
divisions) in any subsequent 24 h&r period
*500 lJV/"C.

(+) or c-j*

30

0574

-

I ’

/ ’
:

0

ip
IT-----3-----J

A

I

I

Y

SERVICE FORM

Model No.
Name

Serial No.

P-0. No. Date

Phone

Company

Address

City

State

Zip

List all control settings and describe problem.

(Attach additional sheets as necessary.)

Show a block diagram of your measurement system including all instruments connected (whether power

is turned on or not). Also describe signal source.

Where is the measurement being performed? (factory, controlled laboratory, out-of-doors, etc.)
What power line voltage is used?

Frequency?

Variation?

Ambient Temperature?

OF. Rel. Humidity?

Variation?

OF.

Other?

Any additional information. (If special modifications have been made by the user, please describe below.)

*Be sure to include your name and phone number on this service form.

Addendum
29103-C-l

u/a/a3

Instruction Manual Addendum

Model 427 Current Amplifier

The following change information is provided as a supplement to thk manual in order to provide the

user with the latest improvements and changes to the manual in the least amount of time. It is recom­mended that this information be incorporated into the appropriate places in the manual immediately.

Replace the information contained in step 8, page 28, under Amplifier Rise Time, with the following
procedure:

8. Amplifier Rise Time
a. Connect the Function Generator to the Model 427 input and connect the Modal 427 rear panel

output to the oscilloscope using the test setup shown in Figure 24.

b. Adjust the 109 through 101’ rangas within the specified lo%-90% rise time using the triangular

wave frequency and adjustment listed in Table 7-2. Adjust the Function Generator, as needed, to

obtain a 10 Volt p-p output from the Model 427.

c. Without altering the test sat-up, verify that the 10 through to8 ranges meet the rise time

specifications in Table 7-2. Adjust the Function Generator, as required to obtain a 10 Volt p-p out-

put from the Modal 427. There should be no overshoot on any range.

d. Remove the 1OOpF capacitor from the test set-up and connect the Function Generator directly to

the Modal 427 input. Verify the 101 through 106 10% -90% rise time, using the square wave fra­quency. per Table 7-2. There should be no overshoot on any range except for the 104 V/A which
should be lass than 10% overshoot.

. .

m INSTRUMENTS

Model 427 Current Amplifier Addendum

INTRODUCTION

This addendum to the Model 427 Current Amplifier Instruction Manual is being provided in order to supply
you with the latest information in the least possible time. Please incorporate this information into the manual
immediately.

Page 3; Note that in Figure 2 the dials on the knobs are now black.

29103-c-2 /7-90

Page 20; Replace Table with the following:

(“100” SERIES, PC-291’, PC-292)

FILTER BOARD

CAPACITORS

clrcult
Deslg.

Cl01
Cl 02 68OPF 5oov
Cl 03
Cl04
Cl05
Cl06
Cl07
Cl06 .66PF 2oov
C109’

c110* 6.6pF 2oov
Cl11 66PF
Cl12 33OpF 5oov
Cl13
Cl14 .0033pF 5oov
Cl 15’
Cl16
Cl17 .lj~F 2oov
Cl16 .33yF 2oov

Cl19’
Cl20 3.3pF
Cl21
Cl 22
Cl23 33pF 1 oov
Cl24 1 OOpF

Value

15OpF

.0022pF
68OOpF
.022pF
.066pF
.22kF 2oov

2.2kF

.OOlpF
.OQF

.033pF

1P

5pF
5pF

Rating
5oov

5oov
5oov
2oov
1 oov

2oov

5oov
5oov
2oov

1 oov

2oov
2oov
1 ooov
1 ooov

1 oov

Type

P0ly

Poly
Poly
Poly
Poly

MY
i;

MY
MY

Poly
Poly
Poly
Poly
Poly

MY
1;

i;
CerD

CerD
CerD
CerD

Mfr.
Code

71590 CPR-IBOJ
71590 CPR-660J
71590 CPR-2200J
71590 CPR-6800J
64171 2PJ-223G

68460 3FR-663-l E

13050 SMIA-.22kF
13050 SMlA-.66pF

13050 SMIA-2.2kF
97419 M2WF-6.6pF
71590 CPR-66J
71590 CPR-330J
71590 CPR-IOOOJ
71590 CPR-3300J
64171 2PJ-103G
66480 3FR-333-l E
13050 SMIA-.lkF
13050 SMIA-.33kF
13050 SMlA-IpF
13050 SMl A-~.~FF

72962 DD-050

72962 DD-050
72962 DD-330
72962 DD-101

Mfr.
Deslg.

MISCELLANEOUS

Kelthley
Pall No.

Cl36-15OP
Cl36-660P
Cl36-.0022M
‘X38-6800P
C108-.022M
Cl46-.066M
C47-.22mF
C47-.66mF
C47-2.2M
C203-6.6M
Cl 36.66P
Cl 38-33OP
Cl 36-,001 M
Cl36-.0033M
Cl06-.OlM
‘2146..033M

C47-.I M
C47-.33M
C47-1 M
C47-3.3M
C64-5P
C64-5P
C64-33P
C64-IOOP

Fig.
Ref.

19
19

:i
1:

19
19
16

16
19
19
19

1:
19

1:

;:
;z

19
19

Circuit
Deslg.

JlOl
QAIOI

DlOl

D102
a101
a102
SIOI

J102

-

Type
Connector, IO-Pin, Mini-PV

Integrated Circuit

Diode, Rectifier
Diode, Rectifier
Transistor

Transistor

Switch, Rotary, RISE TIME
Knob, Rise Time
Connector, ENC. UGl094A/U

Cap, BNC, mates with J102

Clrcult
Desig. Value

RI01 7.76kR
R102 6.41 kn
R103
RI04 51.7kn 1%. 1/6W M1F
RI05 IOkn

51.7kQ

Rating

I%, 1/6W MtF
I%, 1/6W MtF
l%, 1/6W MtF

1-i; l/SW

Type

MtF

Mfr.
code

22526
12040
01295
01295
04713
04713
60164

02660

Mfr.
Code

07716
07716
07716
07716
07716

Mfr.
IJesig.

20052
LM30lAN
1

N914
1 N914
2N3903

2N3905
SW-336

31-2221

Mfr.
Desig.

CEA-7.76KR
CEA-6.41 KR

CEA-51.7KR R66-51.7k
CEA-52.7KR R66-51.7k
CEA-1 Om

Kelthley
Part No.

CS-237
IC-24
RF-26
RF-28
TG-49
TG-53
SW-336
KN-46
cs-249
CAP-l 6

Keithley
Part No.

R66-7.76k
R66-6.41 k

R66-1 Ok

Flg.
Ref.

;‘z
ii

19
19

19
2
3

-

Flg.
Ref.

29103-c-2 /7-90

Page 22; Replace Table with the following:

AMPLIFIER BOARD (cont’d)

DIODES

Circuit
Deslg.

D201
D202
D203
D204
D205
D206
D207
D208
D209
D210

Type

Special
Special
Silicon, NPN, Case TO-106
Silicon, NPN, Case

Silicon
Silicon
Silicon
Silicon

k

80164
80164
07263
07263
01295
01295
01295
01295

01295

01295 1 N914

Mfr.
Desig.

24555A
24555A
2N3565
2N3565

1 N645
1 N645
1 N914
IN914
1 N914

MISCELLANEOUS

Chult Mfr. Mfr.
Deslg.

i%,:“’

J201 Not Used
J202 Receptacle, BNC (UG-1094AIU) 02660 31-2221

Type

Integrated Circuit, Operational Amplifier. 07263

Switch, Rotary, GAIN 80164

Knob, Gain

Code Desig.

%E

RESISTORS (*Located on Switch 5201)

Circuit
Lhig. VSIIJS Rating

Type

Mfr.
Code

Mfr.
Desig.

Keithley
Part No.

24555A
24555A
TG-39
TG-39

RF-14 16
RF-14 16
RF-26
RF-26
RF-26 16
RF-28 18

Fig.
Ref.

18

1:

18

Keithley Fig.
Part No. Ref.

IC-26 18

SW-337 18

KN-46 2

cs-249 18

Keithley
Part No.

Flg.
Ref.

R201 1on IO%, 1/4W Comp 44855
R202 lfvm
R203
R204 23.2kn
R205 22.lkn l%, 1/8W MtF 07716
R206 IOkn I%, 1/8W
R207
R206
R209 12.lkn
R210 499n I%, 1/8W
R211 4990 I%, 1/8W
R212
R213 47on IO%, 1/4W, Comp
R214
R215 470R 1 O%, 1/4W Comp
R216 IOR lo%, 1/4W, Comp
R217
R218’ 270k.Q lo%, 1/2W Comp
R219’
R220’ 9000 1 %, 1/2w DCb 91637
R221’ 1ok.Q I%, 1/2w,
R222’ 1ook.Q 1%. 1/2w
R223’ IMn l%, 1/2w
R224 IOMR 1%. 1 w
R225 10BR

1ookQ I%, 1/8W. MtF 07716

18.2kR l%, 1/2w MtF 07718
1ok.Q I%, 1/8W, MtF 07716

1on 1 %, 1/8W MtF 07718
1okQ I%, 1/6W MtF 07716

ion lo%, 1/4W Comp 44655
1 OOR l%, 1/2w MtF 07716

IO%, 1/2W Comp 01121
I%, 1/8W MtF 07716

MtF

I%, 1/8W MtF 07716

MtF 07716
MtF

MtF 07716
MtF 07716
MtF 07718
DCb 91637

l%, 2w DCb 91637

07716

07716
44655
44655

44855
01121

RC07
ELI-1 M
CEA-100kR
CEA-23.2kR
CEA-22.lkQ
CEA-1 Okn
CEC-18.2kQ
CEA-1 Okn
CEA-12.lkn
CEA-499n
CEA-499R
CEA-1 OR
RC07-471
CEA-IOkR
RC07-471
RC07-100
RC07-100
ES-270kn

CEC-IOOR

DCF-l/2-900n

CEC-IOkR
CEC-IOOkR
CEC-1 Ma

DC-I-IOMR

DC-2-l OQ

R76-10
Rl-IM
R88-1 OOk
R88-23.2k
R88-22.1 k
R88-IOk
R94-18.2k
R88-IOk
R88-12.1 k
R88-499
R88-499
R88-10
R76-470
R88-10k
R78-470
R76-10
R76-10
Rl -270k
R94-100
RI 2-900
R94-10k
R94-100k
R94-1 M
Rl3-IOM
Rl4-IO8

18
18
18
18
18
18
18
18
18
18

1:
18

18

::

29103-c-2 I 7.90

Page 24; Replace Table with the following:

ClrCUlt
De&g.

D306
D309
D310
0311
D312

CkUlf

De&g.

J301
J302

QA301
DA302
QA303
5301
5302
5303

Q301
Q302
Q303
5304
F301
F301
T301
P30.5

­DS-301

DS-302

MOTHER BOARD

TYPe

Silicon
Silicon
Silicon
Silicon
Silicon

TYPO

Connector, Mini-PV
Connector, Mini-PV

Integrated Circuit, Voltage Regulator
Integrated Circuit, Voltage Regulator
Integrated Circuit
Switch, Line Voltage
Switch, “PUSH ON’ Power with lamp
Switch. CURRENT SUPPRESS
Knob Amperes

Transistor

Transistor
Transistor. Silicon, NPN. TO-92 Case
Switch POLARITY
Fuse. tt7V. .25a, Slo-Blo.3AG
Fuse, 234V, IIBA. Slo-Blo, 3AG
Transformer
Receptacle, AC
Line cord. mates with P305
Pilot lamp, neon (replacement for 5302)

Pilot Lamp, OVERLOAD

Knob, Fine Adjust

(cont’d)

DIODES (co&d)

Mfr. Mfr.
Code

01295
01295
01295
01295 1 N645
01295

MISCELLANEOUS

Mfr. Mfr.
Code

22526
22526
07263
07263
07263
80164 SW-316
60164
60164

02735
02735
04713
60164
75915
71400
90164
92369
70903
09806
07294

RESISTORS (*Located

Deslg.

IN914
IN914
IN914

IN914

Deslg. Part No. Ref.

47439
47439

UGA7723393
UGA7723393

A749C

PBL-5-BSA3C7A

SW-339
40312

40312
2N3903

SW-236

Ei250

TR-136

AC3G
17256-S
C7A (NE-2P)
CFO3ACSl669

on

Switch S303)

Kelthley
Part No.

RF-28
RF-26
RF-26
RF-14
RF-26

Ketthley Ftg.

CS-236
CS-236
IO-26
IC-25
IC-27
SW-316
SW-340
SW-339
KN-46

._

TG-54
TG-5*

.-_.

TG-49
SW-236
FU-17
FU-20
TR-136
CS-235
co-7
PL-58
PL-51
KN-58

Flg.

Ref.

17
17

;:

-

17
;:

17

17
3
3
20
2

17

17

17
3

3
;0

3

-

-

2

2

Destg.

R301
R302
R303
R304
R305
R306
R307
R306
R309
R310
R311
R312
R313
R314
R315
R316
R317
R316
R319
R320
R321
R322
R323
R324
R325

VdUe
634fl

6.2D

1.37k.D

*oo*

1.24kn

634*

6.2n

1.37la

2oon

1.24kQ

9.09ko
14kR
1kfJ
1 OkR

&%n

lk0
IkQ
14kfl
IOCl
1 Okn
1 OkR
33on
47kn
10kQ

Aatlng

1%. 1/6W

5%, 1/2w Comp

1%. IIBW MtF

0.5w
1%. l/SW
1%. 119w MtF

5%. t /2w Comp

1%. l,QW M1F

0.5w
1%. l/SW MtF
l%, IBW
1%. 1/8W
I%, 1/8W MtF
10%. 1/4w Comp
I%, l/QW
I%, l/BW
I%, 1/6W MtF
I%, 1/6W
1%. 1/6W MIF
10% 1/4w
10%. 114w Comp
IO%, 1/4w
10%. 114w Comp
10%. 114w Comp
1%. 1/2w

TYPO

MtF

­MtF

­MtF

MtF

MtF
MtF

MtF
Comp
Comp

MtF

Mfr.
Code

07716 CEA-6340
01121

07716
60294 3329P-200 RP-98-200
07716 CEA-1.1 k.Q R68-1.24
07716
01121
07716
60294 3329P-200 RP-98-200
07716 CEA-1 .I Icn R68-1.24
07716 CEA-9.09kR
07716 CEA-14kR
07716
44655 RC07-100 R76-10
07716 CEA-1 kn
07716 CEA-9.09kR
07716
07716 CEA-1 kR
07716
44955 RC07-100
44655 RC07-103 R76-t0k
44655 RC07.103
44655
44655 RC07-473
07716 CEC-lOk0

Mfr.
Desig.

EB-6.2n
CEA-1.37kR

CEA-634n
EB-9.2n
CEA-t.37M

CEA-1 kn

CEA-1 kn
CEA-14kn

RC07-331

Kelthley

Part No.

R66-634
RIQ-6.2
R&?-l .37k

R98-634
RIQ-6.2
R88-1.371

R66-9.09k
R99-t4k
R66-1 k

RBB-1 k
RBB-9.09k
RBB-1 k
RBB-I k
R96-14k
R76-10

R76-IOk
R76-330
R76-47k
R94-10k

Flg.

Ref.

17
17
17
17
17

;:
;:

17
17

1:
17
17

;:
17
17
17

;:
17
17
20

29103-C-2 / 7-90

HOW TO INSTALL IC-333

CUT PIN 5 OF THE IC-333.

ii. PIN 1 IXF THE Op AMP GOES INTO THE HOLE IOF PIN 2.

PIN 2 OF THE CIp AMP GOES INTO THE HOLE CiF pIN S.*j:

8.

C. PIN 3 OF THE Op AMP GOES INTO THE HOLE OF PIN 4.

D . PIN 4 OF THE OP iiw GOES INTO THE HOLE OF PIIN 5.

cc

PIN & OF THE OP AMP GOES INTO THE HOLE OF PIN .5.X+

E.

F. PIN 7 OF THE Op AMP GOES INTO THE HOLE OF PIN 3.

G. FIN 3 OF THE OF GMF GOES INTO THE HOLE OF PIN 10.

PIN HOLES 1,7,9 WILL REMAIN EMPTY.

ON THE REVERSE SIDE OF THE PC-&u

=“9 INSTkLL A CAPACITOR

c-64-22pF BETWEEN FINS 3 AND b OF PC BOARD. %*

CHANGE R210 AND R211 FORM R-83-1K TO R-38-3.01K.

REMOVE CAPACITORS C-207,C-203

AND C-20’? FROM THE

CIRCUIT BOARD. THEY ARE NO LONGER NEEDED.

SEE ATTACHED DRAWING.

4

MODEL 427

COMPONENT UYOUTS

rR201-+201 --y-C2031

-

-c107-

FIGURE 18.

component Layout - PC-289.

FIGURE 19.

Component Layout - PC-292.

15