Keithley 502 User manual

INSTRUCTIONMANUAL
MODEL502
MILLIOHMHETER
Kelthley Instruments. Inc.
29776 Aurora Road/Cleveland, Ohio 44139/[phone]

INSTRUCTION MANUAL
MODEL502
MILLIOHMMETER
OCOPYRIGRT 1975, ~ITRLEY INSTRUMENTS, INC.
PRINTED JULY 1977, CLEVELAND, OHIO, U. S. A.

CONTENTS
SECTION
IN'IRODUCTION
.,,...*.........,................................. I
SPECIFICATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...*.. II
OPERATION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III
A. Connections
(1) Low resistances
(2) Higher resistances
B. Procedure
C. Battery Test
D. Precaution5
CIRCUIT DESCRIPTION
..,............,.,.....,................... IV
MAINTENANCE
,...........................,...................... v
A. Batteries
B. Trouble Shooting
C. Schematic, DR 12189 C
D. Tube Voltage Diagram, DR
12256 C
E. Replacement Parts List
0762

MODEL502 MILLIOHMMlKTHH INl'FiODUCTION
SECTION I - INTRODUCTION
The Keithley Model 502 is a battery operated, portable milliohmmeter
for measuring resistances from 0.00003 to 1000 ohms. The instrument
employs an AC testing method, eliminating zero drift and permitting
resistance readings in the presence of DC currents.
presented on a linear scale panel meter. The reading is
Typical applications of the instrument include measurement of con-
tact resistance, conductivity of semi-conductor samples, fuse and
squib testing, and electrolyte conductivity.
Maximum power dissipation in the sample is 2 microwatts, permitting
the measurement of detonator fuses without danger of detonation.
In the measurement of contact resistance, the model 502 may be
considered a "dry circuit" tester. However, the instrument may be
used in the presence of DC biasing currents to measure the change
in resistance caused by these currents.
FIGCFZ 1. Keithley Model 502 MilJiohmmeter with
carrying case open.
l-1

MODEL502 MILLIOHMMETER Ye
::::
SPECIFICATIONS
SECTION II - SPECIFICATIONS
RANGES: The test current, the input vpltage drop, and the power dissipation
(Pd = 2&E,,) for full-scale readings on each range are given below:
tinge,
Ohms Average
Average
Applied Current, Voltage Drop,
Milliamperes Microvolts
Maximum
Dissipation
in Sample,
Microwatts
0.001 10 10 0.2
0.003 10 30 0.6
0.01 10.00 100 2.00
0.03 3.33 100 0.66
0.1 1.00 100 0.2
0.3 0.33 100 0.066
1 0.1 100 0.02
3 0.2 600 0.24
10 0.06 600 0.072
30 0.02 600 0.024
100 0.006 600 0.0072
300 0.002 600 0.0024
1000 0.0006 600 0.00072
ACCURACY: 3% of full scale on all ranges except the O.OOl-ohm range, where
it is 5% of full scale. Less than 2% error is added in measuring samples with
a series reactance of 4% of sample resistance.
OUTPUT: Meter only.
SAFETYAND RELIABILITY: Maximum power dissipation in the sample with improper
range setting is three milliwatts. Maximum dissipation caused by instrument
component failure and improper range setting is six milliwatts.
INPUT ZERO: Lever switch prevents off-scale meter indications while changing
samples.
SPEEDOF RESPONSE: Five seconds to 90% of final reading on all ranges.
ZERODRIFT: None.
REPEATABILITY: D
Within 2/,.
WARMUPTIME: Within 30 seconds.
0963R 2-1

SPECIFICATIONS MODEL502 MILLIOHMMETER
:.
::
BATTERYLIFE: 360 hours minimum. :
BATTERYTEST: An internal resistance standard is measured in the Battery
Test Position to provide a comple<e check of battery condition and proper in-
strument operation.
BATTERYCOMPLEMENT: Two RM 401R, two RM 42R, one 412, one 413.
TUBE COMPLEi%ENT:One 6418, four 6419.
TRANSISTORCOMPLEMENT: Four 2N1381.
ACCESSORIESFURNISHED: Model 5021 Current and Voltage Leads; one set of al-
ligator clips; one set Klipson adapters; mating connectors.
CONNECTORS: Amphenol 80C and 80-PC2F receptacles.
DIMENSIONS:~ 9 inches high x 6 inches wide x 7 inches deep.
NET WEIGHT: 7-l/2 pounds.
'02648

Each test lead has two clips, one with a red insulator and the other with
a black instilator. Use both test leads
to make a connection, making sure
like-color clips are on the same side of the sample (see Figure 2). Connect
the current supply leads to the sample at any point which assures current
flow through the entire sample.
on the sample. This connection may include the leads
CURRENT
Black I
SOURCE
I-+
Connect the voltmeter leads across only
Red
RX that part of the sample which is to be
measured, as shown in Figure 2. If the
terminal or test leads of the resistance
Black Red being measured are included within the volt-
VOLTMETER meter clips, the reading will include the
resistance of these leads.
FIGURE 2.
OPERATION
MODEL502 MILLIOHMMETER
-T
:::
':sECTIONIII - o~mm10N
.A. CONNECTIONS
(1) Lower resistances (less than 3 ohms).
NOTE
Do not connect the red clips to the black clips.
The clip-to-sample resistance of both voltmeter
clips are added in series with the unknown, and
large errors can result.
(2) Higher resistances (3 ohms and greater).
For ranges over 3 ohms full scale, the clip contact resistance is in-
significant compared with the full scale value, so voltage and current
leads may be paired and the standard two-terminal ohmmeter method em-
ployed. Of course, the four-terminal method above may be used, but the
two terminal method is faster for repeated testing.
B. PROCEDURE
Turn the power ON while the READ-SHORTSwitch is at SHORT. The instrument
will stabilize in about 15 seconds.
Connect the leads to the sample as outlined above. Then IIIOW the RRAD-
SHORTswitch to RF,AD. Rotate the OHMSFULL SCALE switch until a suitable
on-scale reading is obtained.
The READ-SHORTswitch shorts the voltage input in the SHORTposition.
It keeps the meter pointer on scale while the test leads are being connected
to an unknown. If an overload is applied to the input by inadvertently
opening the READ-SHORTswitch, no damage will result.
However,
approxi-
mately 30 seconds will be required for the amplifier to recover.
0264~ 3-l

O-ON
MODEL5tX MILlJon :
C.
BATTERYTEST :.
Before a reading is made, it may be desirable to check overall cir-
cuit operation. This is d&e by rotating the range switch to BATI?, -
TEST and switching the BEAD-SHORTswitch to.BEAD. The meter should
reati within 1% divisions of the red line on the meter face marked
BATTERY TEST. Failure of-the unit to read within these limits indicates
a circuit failure which, in most cases, will be battery failure.
Consult SEmION V - MAIWPEB4NC.Efor battery changes or troubleshoot-
ing information.
PRECAUTIONS
On full scale ranges of one ohm and below, the amplifier has sensi-
tivities in the microvolt region and a pass band which includes 60
cps. Thus, a loop in the voltage leads which encloses any 60 cps
magnetic field may give a meter indication. Care should be exercised
to avoid such magnetic loops. .Care should also be taken in shielding
critical circuits to avoid 60 cps pickup from electric fields; in
general, however, the electrostatic pickup is not serious at the im-
pedance involved. One way to test for pickup is to remove. the cur-
rent supply leads with the voltage leads connected to the sample.
If no reading appears on the meter, no pickup is present. If some
reading does occur due to the presence of 60 cps magnetic field, it
may be reduced to a minimum by rotating the meter for minimum pickup.
In any case, the instrument reads correctly above any residual read-
ing. For example, if the 502 reads, say, .002 ohms due to the pres-
ence of stray fields with the voltmeter leads shorted, a .003 ohm
resistance being tested will still read ,003 ohms. This is because
the 60 cps signal is superimposed on the 100 cps square wave test
signal. Thus the 60 cps signal is not rectified and the meter reads
only the rectified square wave.
Because of the AC technique employed, inductive and capacitive com-
ponents in the test impedance may cause some waveform distortion and
erroneous readings. Series inductive impedance (at 100 cps) less
than 20% of the resistance cause the reading to be less than 2% high.
Shunt capacitive admittance (at 100 cps) less than 6% of the.hiduct-
ante cause the reading to be less than 2% low, Listed below are the
limiting values of inductance and capacitance to cause 2% error at
full scale on any range:
RANGE MAX SERIES INDUCTANCE h¶AXSHUNTCAPACITANCE
.OOl ohms
.003
.Ol
.03
.1
.3
1.0
1%
30
100
300
1000
.3 microhenries
.9
3
309
go.3 millihenries
3.9
309
90.3 henries
I
over
1000 microfarad
I
750 microfarad
mJ
::
7.5
2.5
l
3-2 0762

KODEL 502 MILLIOHMMEEER OI'FSWITON
It is well to remember that basically, the Model 502 is measuring
the voltage acro& the sample resistance due to current flow in
the sample. So lpng as the sample current is generated by the
Model 502, no difficulties should be encountered. However, if
other currents are flowing in the sample in addition to the test
current, these currents must be either small compared with the
test current or essentially dc. The Model 502 will read a resistor
in the milliohm region which is carrying more than 50 amperes of
direct current, but even .Ol amperes of alternating current whose
frequency is within the pass band of the amplifier will cause a
serious error.
When measuring samples across which a dc voltage greater than about
.05 volts may appear, a blocking capacitor should be used in series
with one current lead and another capacitor in series with one volt-
age lead. Use 1000 mfd at a voltage rating sufficient to handle the
dc sample voltage.
Values of r and C are shown below:
Range
.l
.Q
.Ol
.003
.OOl
The setup is shown in Fig. 3.
If this arrangement is to be
used on the ranges below .3
ohm, also include r as shown.
This resistor is to provide
a d.c. return path for the
output transistor, Qk.
2
100
2
10
10
C
-
1OCOmfd
1000
boo0
LOO0
LOO0
Added error
-1%
-3%
-6%
-6%
-6%
0264R 3-3

MODEL502 MILLIOM&!E!VBR CIRCUIT DESCRIPTION
SECTION IV - CIRCUIT DESCRIPTION
The standard method of measuring resistance assumes that test lead re-
sistance is negligible. When measuring resistances at or below the
level of lead resistance, a more sophisticated approach is required.
The four-terminal method of resistance measurement consists of supply-
ing current from an isolated current generator to the sample, and
measuring the voltage drop across the sample with an isolated voltmeter.
The generator is made to supply constant current regardless of lead
resistance so that no errors occur due to current lead connection,
The voltmeter has large enough input resistance so that the voltage
lead resistance does not cause any error. Since there is no current
error and voltage error, the resistance is read correctly.
The 502 circuit consists of two parts, a 100 cps transistor squarewave
generator supplies the current across the sample and the AC microvolt
meter measures the voltage drop. The panel meter is calibrated directly
in ohms on a linear scale. Refer to the circuit diagram, DR 12189-C.
(1) Square W-ix Generator. The 100 cps square wave is generated by
a transistor multivibrator consisting of Ql and Q2. Rlb6 is a symmetry
control which is set at the factory to give a symmetrical square wave.
This adjustment is necessary to insure no change in reading when the
current leads are reversed. Q3 and Qk serve as a power amplifier.
Transistor Qh acts essentially as a 100 cps switch connecting and dis-
connecting El across the sample and series resistors Rl32 through
Rllr2. Due to the fact that the output peak voltage is more than 95%
of the mercury battery voltage, the change in square-wave amplitude
with change of transistor parameters is very small. B6 supplies a
small negative bias current through R151 to the output transistor to
insure good cut off characteristics, at a high ambient temperature.
(2) AC Amplifier. 'Ihe ac amplifier is a conventional vacuum tube
voltmeter with meter current feedback. The input signal is matched
to the vacuum tube input by an input transformer on the more sensitive
ranges. Above 1 ohm, the input transformer is not used.
The input voltage is compared to the feedback voltage through RlOl and
RI02 into the grid of Vl. Vl, V2, V3, Vk, and V5 amplify the error
signal. The output voltage is full-wave rectified by Dl and D2 to
supply indicating meter current. The ac current through the meter
and rectifiers flows in R128, R129 or R130 to supply feedback voltage
to the first stage. The dividers R103 and R126 or R127 allow separate
calibration of the ranges which employ transformer input and the
ranges which do not.
ON BATTERYTEST, the unit is automatically placed on the 1000 ohm
range. A 500 ohm resistor, Rlk9, is connected into the test position
and the external current and voltage leads are disconnected. Since
battery current drain is essentially the ssme on all ranges, this
test will indicate faulty batteries Immediately by giving a reading
less than normal.
0762 4-1

MDDEL502 MILILO~IMMETER MAINTENANCE
:.
;;SECTICN V - MAINTENANCE
A. BATTERIES
Under ncrmal conditions the only maintenance required will be the
replacement of batteries. To reach the batteries, remove the four
screws at the rear and slide the instrument out of the case. The
batteries are all located in holders at the top of the instrument.
Bl, supplying the current generator, and B3, which supplies the
vacuum tube filaments, should have a useful life of about I460 hours
unless the instrument is used continuously on the lowest three ranges.
This may shorten the life of Bl to 360 hours. Bh, which supplies
plate potential to the output tube should last thrcugh about two
changes of Bl and B3. B2, the bias battery, B5, the plate supply
for the amplifier, and B6, the negative bias for the output tran-
sistor, should last about two years. To be certain of always having
fresh batteries, a good practice would be to change all batteries
whenever one of the set needs replacement.
B. TROUBLE-SHOOTING
If the circuit fails to perform properly and the batteries are found
to be good, a step-by-step procedure should be followed to discover
the fault.
First check the current supply wave form at the current output termi-
nals. This should be a 100 cps square wave about 1.3 volts amplitude.
Switch to the 1 ohm range so that oscilloscope loading will not affect
the wave form. If the desired wave form is not present, check the
generator circuit stage by stage. Ql and Q2 are connected as a multi-
vibrator. Q3 and Qk are cascaded emmitter followers which develop
the output current drive.
If the current supply works properly, check the voltage amplifier.
First compare observed operating potentials with those given in the
Voltage Diagram in this section. When operating points are all cor-
rect, the amplifier may be checked stage by stage for amplification.
Note that V5 is used to supply current to the meter, and therefore
has a voltage gain of only about one.
The voltage required at the junction between Cl15 and the meter
diodes for full scale deflection is approximstely 0.75 volt RMS.
The Voltage Diagram, DR 12256-4, Circuit Schematic, DR 12189-u and
parts list are included at the back of the manual.
0762 5-l

l
MODEL502 MILLIOHMMETER REPLACEABLEPARTS
.
:L::
S!iCTION 6. REPLACEABLEPARTS
6-1. REPLACEABLEPARTS LIST. The Replaceable Parts List describes the com-
ponents of the Model 502 and its accessories. The List gives the circuit de-
signation, the part description, a suggested manufacturer, the manufacturer's
part number and the Keithley Part Number. The name and address of the manu-
facturers listed in the "Mfg. Code" column are contained in Table 2.
6-2. HOWTO ORDKRPARTS.
a. For parts orders, include the instrument's model and serial number,
the Keithley Part Number, the circuit designation and a description of the
part. All structural parts and those parts coded for Keithley manufacture
(80164) must be ordered from Keithley Instruments, Inc. In 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 distributor or the Sales
Service Department, Keithley Instruments, Inc.
camp
ETB
f
k
M or meg
m
Mfg.
MtF
Mil. No.
MY
ampere
Composition
Deposited Carbon
Electrolytic, tubular
farad
kilo (103)
mega (106) or megohms
milli (10-3)
Manufacturer
Metal Film
Military Type Number
Mylar
R
PM
Poly
P
II
”
Var
w
ww
WWVar
ohmohm
Paper,Paper, metallizedmetallized
PolystyrenePolystyrene
pica (lO-l2)pica (LO-l2)
micro (10-6)micro (10-6)
voltvolt
VariableVariable
wattwatt
WirewoundWirewound
Wirewound VariableWirewound Variable
TABLE 1. Abbreviations and Symbols.
0764R 6-1

REPLACEABLEPARTS MODEL502 MILLIORMMETER
MODEL502 REPLACEABLEPARTS LIST
(Refer to Schematic Diagrani 121891) for circuit designations.)
BATTERIES
Circuit
Desig.
Bl
B2
B3
,B4
B5
B6
B7
B8
Description
1.3 v mercury
1.35 v mercury
1.3 v mercury
8.4 v mercury
1.35 v mercury
8.4 v mercury
8.4 v mercury
8.4 " mercury
Mfg. Mfg. Keithley Fig.
Code Part No. Part No. Ref.
37942 RM42R BA-10
10608 E401 BA-8
31942 RM42R BA-10
10608 El46 BA-9
10608 E401 BA-8
10608 El46 BA-9
10608 El46 BA-9
10608 El46 BA-9
~CAPACITORS
Circuit Mfg. Mfg. Keithley Fig.
Desig. Value Rating Type Code Part No. Part No. Ref. _
Cl01
Cl02
Cl03
Cl04
Cl05
2 Pf
.0022 pf
.0082 pf
.22 !Jf
2 Pf
Cl06 .OOl uf
Cl07 270 pf
Cl08 .22 IJ.f
Cl09
2 Pf
Cl10 .OOOl uf
Cl11
Cl12
Cl13
Cl14
Cl15
820 pf
.22 wf
2 Pf
.l nf
.1 wf
Cl16
Cl17
Cl18
Cl19
Cl20
0.1 uf
1 (If
1 Pf
50 Kf
50 pf
Cl21
Cl22 820 pf
22 pf
50 "
200 v
100 v
50 v
50 v
100 v
500 v
50 v
50 "
500 v
300 "
50 v
50 v
50 v
50 v
50 v
200 v
200 "
50 I!
50 v
300 v
500 v
ETB 37942
Poly 00686
MY 84411
MY 84411
ETB 37942
Mica 84171
Mica 84171
MY 84411
ETB 37942
Mica 84171
Mica
MY
ETB
MY
MY
MY
PM
PM
ETB
ETB
84171 DM15-821K
84411 601PE
37942 TC302
84411 601PE
84411 601~~
84411 601PE
00656 P8292ZN
00656 P8292ZN
37942 TC39
37942 TC39
Mica 84171
Mica 84171
TC302
663UW-100
601PE
TC302
DM15-102.J
DM15-271.J
601PE
TC302
DM15-1Ol.J
DM15-821.J
DM15-220J
C39-2M
C55-2200P
C38-.0082M
C41-.22M
C39-2M
c21-1OOOP
C21-270P
C41-.22M
C39-2M
c21-loop
c21-82OP
C41-.22M
C39-2M
C41-.lM
C41-.lM
C41-.lM
CLB-LM
Cl&1M
C39-50M
C39-50M
CZl-820P
c21-22P
6-2 0764R

MODEL502 MILLIOHPlMETER REPLACEABLEPARTS
Circuit
Desig.
Dl
D2
.,:; DIODES
Mfg. Keithley Fig.
Type Number Code Part No. Ref.
Silicon lN645 01295 RF-14
Silicon lN645 01295 RF-14
MISCELLANEOUSPARTS
Circuit
Desig. Description Mfg.
Code Keithley
Part No. Fig.
Ref.
Jl
---
52
---
Ml
Sl
52
s3
_--
Tl
Circuit
Receptacle, Microphone, Voltage
(Mfg. No.~ 80-C)
Plug, Microphone, Mate of Jl
(Mfg. No. 80-M)
Receptacle, Microphone, Current
(Mfg. No. 80PC2F)
Plug, Microphone, Mate of 52
(Mfg. No. 80MCZM)
Meter (O-SO vamp)
Switch, DPDT, ON (Mfg. No. 830532)
Toggle Switch, READ-SHORT(Mfg.
No. 3003-DL)
Rotary Switch less components,
OHMSFULL SCALE
Knob Assembly, Ohms Switch
Transformer
RESISTORS
Mfg.
02660
02660
02660 CS-32
02660 cs-33
80164 ME-13
04009 SW-l76
82389
80164 SW-57
80164 16323A
80164 TR-53
Mfg.
cs-34
cs-35
SW-59
Keithley Fig.
Desig. Value Rating Type Code Part No. Part No. Ref.
RlOl
R102
R103
R104
R105
1Wl l%, l/2 w MtF 07716 MECT-8 R53-1M
lM0 l%, l/2 w MtF 07716 MECT-8 R53-1M
60 kn l%, l/2 w DCb 79727 CFE-15 R12-60K
2.2 m l%, l/2 w DCb 79727 CFE-15 R12-2.2M
10 MO lO%, l/2 w Comp 01121 EB Rl-1OM
RlO6
R107
R108
R109
RllO
100 kfl lO%, l/2 w camp 01121 EB Rl-1OOK
22 m lO%, l/2 w Comp 01121 EB Rl-22M
2.2 Mrl lO%, l/2 w Comp 01121 EB Rl-2.2M
2.2 I%? lO%, l/2 w Comp 01121 EB Rl-2.2M
10 wl lO%, l/2 w Comp 01121 EB Rl-1OM
1164R
c
6-3

REPLACEABLEPARTS MODEL502 MILLIOHMMETER
5
~XESISTORS(Cont'd)
::::
Circuit Mfg. Mfg. Keithley Fig.
Desig. Value Rating Code Part No. 0
TYPO Part No. Ref.
Rlll
Rll2
R113
R114
R115
R116
R117
R118
R119
R120
R121
R122
R123
R124
R125
R126
R127
Rl28
R129
R130
R131
R132
Rl33
R134
R135
R136
R137
R138
R139
R140
R141
R142
R143
R144
R145
R146
R147
Rl48
R149
R150
100 kn
22 m
2.2 IQ
2.2 ml
10 I%l
100 kfl
22 Mrl
2.2 MO
2.2 M
10 m
2.2 lm
47 kn
5 kn
5 kn
1.8 kn
1 kn
100 n
s91 n
300 n
1 kn
47 ko
60 n
180 n
600 n
1.8 kn
6 kQ
3 kn
10 kc
30 kn
100 kn
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
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%, 5 w
lO%, 5 w
l%, l/2 w
l%, l/2 w
1%, l/2 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
l%, l/2 w
l%, l/2 w
l%, l/2 w
l%, l/2 w
l%, l/2 w
l%, l/2 w
l%, l/2 w
l%, l/2 w
l%, l/2 w
lO%, 2 w
1%, l/2 w
l%, l/2 w
l%, l/2 w
l%, l/2 w
camp 01121 EB Rl-100K
Comp 01121 EB Rl-22M
Comp 01121 EB Rl-2.2M
Comp 01121 EB Rl-2.2M
Comp 01121 EB Rl-1OM
Camp 01121 EB Rl-100K
Comp 01121 EB Rl-22M
Comp 01121 EB Rl-2.2M
Comp 01121 EB Rl-2.2M
Comp 01121 EB Rl-1OM
Comp 01121 EB Rl-2.2M
Comp 01121 EB Rl-47K
DCb 79727 CFE-15 R12-SK
DCb 79727 CFE-15 R12-5K
DCb 79727 CFE-15 R12-1.8K
wwvar 71450 AW RP3-1K
wwvar 71450 AW RP3-100
DCb 79727 CFE-15 R12-91
DCb 79727 CFE-15 Rl2-300
DCb 79727 CFE-15 R12-1K
Camp 01121 EB Rl-47K
DCb 79727 CFE-15 RlZ-60
DCb 79727 CFE-15 R12-180
DCb 79727 CFE-15 R12-600
DCb 79727 CFE-15 R12-1.8K
DCb 79727 CFE-15 RlZ-6K
DCb 79727 CFE-15 R12-3K '.
DCb 79727 CFE-15 R12-10K "
DCb 79727 CFE-15 RLZ-30K
DCb 79727 CFE-15 RlZ-100K
DCb
DCb
DCb
DCb
DCb
79727
79727
79727
79727
79727
71450
79727
79727
79727
79727
CFE-15 RlZ-300K
CFE-15 R12-1M
CFE-15 R12-82
CFE-15 RlZ-3K
CFE-15 R12-7K
wwvar
DCb
DCb
DCb
DCb
WP RP9-1OK
CFE-15 R12-7K
CFE-15 RlZ-3K
CF&15 RlZ-500
CFE-15 R12-1M
"Nominal value, factory set.
6-4
1164R
l

MODEL502 MILLIOHMMETER REPLACEABLEPARTS
RESI'STORS(Cont'd)
Circuit Mfg. Mfg. Keithley Fig.
Desig. Value Rating TYPO Code Part No. Part No. Ref.
R151 15 kfi lO%, 112 w Comp 01121 EB Rl-15K
R152 47 kn lO%, l/2 w Comp 01121 EB Rl-47K
R153 210 n l%,
l/2 w DCb 79727 CFE-15 R12-210
Rl54 10 MCI lO%,
l/2 w Comp 01121 EB Rl-1OM
TRANSISTORS
Circuit
Desig.
Ql
;:
Q4
Mfg. Keithley Fig.
Number Code Part No. Ref.
2N1381 01295 TG-8
2N1381 01295 TG-8
2N1381 01295 TG-8
2N1381 01295 TG-8
VACUUMTUBES
Circuit
Desig. Number Mfg.
Code Keithley Part No. Fig. Ref.
Vl 6419 81453 EV-CK6419
v2 6419 81453 EV-CK6419
v3 6419 81453 EV-CK6419
v4 6419 81453 EV-CK6419
v5 6418 80164 EV-6418-1
FURNISHEDACCESSORIES
Description Mfg.
Code Mfg. Part No. Keithley
Part No.
Two Alligator Clips, red 83330
Two Alligator Clips, black 83330
Two Miniprod Adapter Tips, red 08811
Two Miniprod Adapter Tips, black 08811
~~~~Model5021 Voltage Lead, includes 80164
.Plug, Microphone 02660
.Phone Tip, Red 83330
.Phone Tip, Black 83330
"g<Model 5021 Current Lead, includes 80164
.Plug, Microphone 02660
.Phone Tip, Red 83330
*Phone Tip, Black 83330
>wcModel 5021 is a set of current and voltage leads.
304 AC-3R
304 AC-3B
33-160 PP-3R
33-162 PP-3B
80-M cs-35
237 PP-2R
237 PP-2B
80MC2M cs-33
237 PP-2R
237 PP-2B
1164R 6-5

REPLACEABLEPARTS MODEL502 MILLIOHMMFXER
:,,
10656 Aerovox Corp.
New Bedford, Mass. ,.. 71450 CTS Corp.
Elkhart, Ind.
10686 Film Capacitors, Inc. 75042 International Resistance Co.
New York, N. Y. Philadelphia, Pa.
11121 Allen-Bradley Corp.
Milwaukee, Wis.
11295 Texas Instruments, Inc.
Semi-Conductor-Components Division
Dallas, Texas
79727 Continental-Wirt Electronics
Corp.
Philadelphia, Pa.
80164 Keithley Instruments, Inc.
Cleveland, Ohio
,266O Amphenol-Borg Electronics Corp. 81453 Raytheon Co.
Broadview, Chicago, Illinois Industrial Components Div.
Industrial Tube Operation
j4009 Arrow-Hart and Hegeman Electric Co. Newton, Mass.
Hartford, Corm. 82389 Switchcraft, Inc.
)7716 International Resistance Co.
Burlington, Iowa Chicago, Ill.
)8811 G-C Electronics Co., Inc.
Camden, N. J.
83330 Smith, Herman H., Inc.
Brooklyn, N. Y.
10608 Union Carbide Corp.
New York, N. Y.
84171 Arco Electronics, Inc.
Great Neck, N. Y.
37942 Mallory, P. R., and Co., Inc.
Indianapolis, Ind.
84411 Good-All Electric Mfg. Co.
Ogallala, Nebr.
TABLE 2. Code List of Suggested Manufacturers. (Based on Federal Supply Code
for Manufacturers, Cataloging Handbook H4-1.)
6-6 1164R

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