Keithley 8009 Instruction Manual

Model 8009 Resistivity Test Fixture

Instruction Manual

99 Washington Street
Melrose, MA 02176

800.517.8431

TestEquipmentDepot.com

Contains Operating and Servicing Information

8009-901-01 Rev. C

A GREATER MEASURE OF CONFIDENCE

WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and
workmanship for a period of 1 year from date of shipment.

Keithley Instruments, Inc. warrants the following items for 90 days from the date of ship­ment: probes, cables, rechargeable batteries, diskettes, and documentation.

During the warranty period, we will, at our option, either repair or replace any product that
proves to be defective.

To exercise this warranty, write or call your local Keithley representative, or contact Kei­thley headquarters in Cleveland, Ohio. You will be given prompt assistance and return
instructions. Send the product, transportation prepaid, to the indicated service facility.
Repairs will be made and the product returned, transportation prepaid. Repaired or
replaced products are warranted for the balance of the original warranty period, or at least
90 days.

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from product modification without Kei­thley’s express written consent, or misuse of any product or part. This warranty also does
not apply to fuses, software, non-rechargeable batteries, damage from battery leakage, or
problems arising from normal wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTHER W
IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR USE. THE REMEDIES PROVIDED HEREIN ARE
BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES
SHALL BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF ITS INSTRU­MENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS BEEN
ADVISED IN ADVANCE

OF THE POSSIBILITY OF SUCH DAMAGES. SUCH
EXCLUDED DAMAGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS
OF REMOVAL AND INSTALLATION, LOSSES SUSTAINED AS THE RESULT OF
INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY.

ARRANTIES, EXPRESSED OR

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Model 8009 Resistivity Test Fixture

Instruction Manual

©2008, Keithley Instruments, Inc.

Test Instrumentation Group

All rights reserved.

Cleveland, Ohio, U.S.A.

May 2008, Third Printing

Document Number: 8009-901-01 Rev. C

SAFETY PRECAUTIONS

The following safety precautions should be observed before using this product
and any associated instrumentation. Although some instruments and accessories
would normally be used with non-hazardous voltages, there are situations where
hazardous conditions may be present.

This product is intended for use by qualified personnel who recognize shock haz­ards and are familiar with the safety precautions required to avoid possible injury.
Read the operating information carefully before using the product.

Exercise extreme caution when a shock hazard is present. L
present on cable connector jacks or test fixtures. The American National Stan­dards Institute (ANSI) states that a shock hazard exis
er than 30V RMS, 42.4V peak, or 60VDC are present. A good safety practice is

to expect that hazardous voltage is present in any unknown circuit before
measuring.

Before operating an instrument, make sure the line cord is connected to a proper­ly grounded power receptacle. Inspect the co
jumpers for possible wear, cracks, or breaks before each use.

For maximum safety, do not touch the product, test cables, or
ments while power is applied to the circuit under test. ALWAYS remove power
from the entire test system and discharge any capacitors before: connecting or
disconnecting cables or jumpers, installing or removing switching cards, or mak­ing internal changes, such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of
the circuit under test or power line (earth) ground. Always make measurements
with dry hands while standing on a dry, insulated surface capable of withstanding
the voltage being measured.

Do not exceed the maximum si
defined in the specifications and operating information, and as shown on the in­strument or test fixture rear panel, or switching card.

t connect switching cards directly to unlimited power circuits. They are

Do no
tended to be used with impedance limited sources. NEVER connect switching
cards directly to AC main. When connecting sources to switching cards, install
protective devices to limit fault current and voltage to the card.

gnal levels of

nnecting cables, test leads, and

the instruments and accessories, as

ethal voltage may be

ts when voltage levels great-

any other instru-

in-

When fuses are used in a product, replace w
protection against fire hazard.

ith

same type and rating for continued

Chassis connections must only be used as shield connections for measuring cir­cuits, NOT as safety earth ground connections.

If you are using a test fixture, keep the lid closed while power is applied
device under test. Safe operation requires the use of a lid interlock.

If a screw is present on the test fixture, connect it to safety
#18 AWG or larger wire.

The symbol on an instrument or accessory indicates that 1000V or more
be present on the terminals. Refer to the product manual for detailed operating in­formation.

Instrumentation and accessories should n

Maintenance should be perfo
forming any maintenance, discon

rmed by qualified service personnel. Before per-

ot be connected to humans.

nect the line cord and all test cables.

earth ground using

to the

may

Specifications

Operating Voltages:

1kV Peak Source (safety banana plugs supplied with 6517).
200V Peak Measure (triax, 3­200V Peak Common mode.

0.1A Peak Test Current.
1VA.

Volume Resistivity Range:
Surface Resistivity Range: 10
Center Electrode: 50.8mm O.D. ± 0.05mm (2.0 in.
Electrode Concentricity: Within 0.01 in. of
Ring Electrode: 57.2mm I.D. ± 0.05mm (2.25 in.
Top Electrode: 85.7mm O.D. ± 0.05mm, (3.375

in.) conductive rubber pad.

Electrode Material:
Pad Durometer: 70 Shore A.
Pad

Resistivity: Volume = 10¾/square max
Sample Size (Min.): 63.5mm diameter
Sample Size (Max.): 101.6mm sq. × 3.2mm thick (4 in. × 0.125 in.).
Inte

rlock: 4 pin for use with 6517
Test F o rc e:

Center Electrode: 6 lbs.

Ring Electrode: 2 lbs. min.; 9.3 psi, 64.1 kPa.

Operating Temperature:
Operating Humidity: 0% R.H. to 65% R.H. up to 35°C,

degree above 35°C.

Dimensions: 107.95mm high × 165.1mm wide × 139.7mm deep (4.25 in. × 6.5 in. × 5.5

in.).

Weight:

1.45kg (3.19 lbs.).

Typ

lug).

103 to 1018 Ohm-cm.

3

to 1017 Ohm.

± 0.002 in.) conductive rubber pad.

center of ring electrode.

± 0.002 in.).

in. ± 0.002 in.), 54mm diameter (2.125

e #303 Stainless.

.

(2.5 in.) (surface).

.

min.; 1.9 psi, 13.2 kPa.

10 lbs max.; 3.2 psi, 21.9

23 lbs. max.; 107 psi, 737.6 kPa
(dependent upon sample thickness).

–30°C to +80°C.

kPa.

linearly derate 3% R.H. per

Specifications subject to change without notice.

Table of Contents

Section 1 — General Information

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Supplied accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 Safety information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Section 2 — Operation

2.1 Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 ASTM standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 Insulator sample mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.4 Model 6517 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.5 Model 6517B connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.6 Test voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.7 Current measurement range and compliance limit .

2.8 Electrification time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.9 Resistivity measurement procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Section 3 — Derivation of Resistivity Equations

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2 Calculating resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.3 Resistivity nomographs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.4 Derivation of resistivity equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

. . . . . . . . . . . 11

. . . .

Section 4 — Maintenance

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.2 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.3 Replaceable parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

i

List of Illustrations

Section 2 — Operation

Figure 2-1 Model 8009 resistivity test fixture . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 2-2 Model 8009 schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 2-3 Connecting the Model 6517 Electroemter/High Resistivity

Meter to the Model 8009 test fixture . . . . . . . . . . . . . . . . . . . . . 9

Figure 2-4 Connecting the Model 6517B Electroemter/High Resistivity

Meter to the Model 8009 test fixture . . . . . . . . . . . . . . . . . . . . 10

Section 3 — Derivation of Resistivity Equations

Figure 3-1 Basic measurement techniques . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 3-2 Surface resistivity (σ) nomograph

Figure 3-3 Volume resistivity (ρ) nomograph . . . . .

Figure 3-4 Electrode dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

. . . . . . . . . . . . . . . . . . . . . . 15

. . . . . . . . . . . . . . . . . 16

ii

List of Tables

Section 4 — Maintenance

Table 4-1 Model 8009 replaceable parts list . . . . . . . . . . . . . . . . . . . . . . . 22

iii

Blank page.

iv

General Information

1.1 Introduction

1

This packing list contains information on using the Model 8009 Resistivity Test
Fixture. The Model 8009 allows volume resistivity measurements up to 10
ohm-cm or surface resistivity measurements up to 1017Ω. The test fixture is
designed using a three-lug triax connector that allows simple connection to a
Keithley Instruments Model 6517, 6517A, or Model 6517B Electrometer.

NOTE

All references in this manual to the Keithley Instruments
Mo

del 6517 are also valid

Model 8009 features

All electrodes made from stainless steel for corrosion prevention.

Switchable volume/surface resistivity modes.

Operates with Keithley Instruments Model 6517 and Model 6517B Electrometer/
High Resistance Meters.

Safety interlock system and dual safety banana jacks for connection to 1kV

rce

in Model 6517 and Model 6517B.

sou

for the Model 6517A.

18

1.2 Supplied accessories

The following accessories are supplied with the Model 8009 test fixture:

• Model 6517-ILC-3: 3

• Model 6517B-ILC-3: 3

• Model 7078-TRX-3: A 3

- meter, 4-pin interlock cable.

- meter, 4-pin interlock cable.

ft. (0.9m) low noise triaxial cable that is

1

terminated at both ends with 3-slot triaxial connectors. Used to connect the

!

Model 8009 test fixture to the Model 6517 Electrometer.

• 8007-GND-3: Safety g

round wire with ground lug.

1.3 Safety information

Safety symbols and terms

The following terms and symbols are found on the test equipment, or used in this
packing list.

The symbol on an instrument denotes the user should refer to the
appropriate operating in

The symbol on an instrument denotes that 1000V or more may be present on
the terminal(s). Use standard safety precautions to avoid personal contact with
these vo

The W
death. A
procedure.

ltages.

ARNING heading indicates hazards that may cause personal injury or

lways read over the information very carefully before performing the

struction

s.

The CA
Such damage may invalidate the warranty

The ground screw must be connected to a safety earth ground as explained
in Section 2.

UTION heading explains hazards that could damage the instrument.

.

Safety precautions

WARNING

To avoid possible personal injury or death caused by elec­t

ric shock, the following safety precautions must be
observed when using the Model 8009 Resisti
ture.

1. Resistivity tests typically use lethal voltage levels. Safe operation requ
oper use of the lid interlock.

the pr

2. Before use, connect the test fixture screw term

2

vity Test Fix-

inal to a safety earth ground

ires

using the Model 8007
wire.

3. Do not exceed 1000V or 1A at the test fixture input triax connector.

4. Turn off the voltage source before connecting or disconnecting wires or

cables in the test system.
Use the supplied triax cable and test leads to ensure that

5.

faces are exposed during the test.

6. After the test, set the voltage source to 0V and wait for the source to

discharge before openi

The Model 8009 Test Fixture includes a 10cm square, 1mm
thi

ck test sample. For
should always be stored with this sample between the elec­trodes.

-GND-3 safety ground wire or #18 AWG (or larger)

no conductive sur-

ng the lid of the test fixture.

NOTE

maximum protection, the Model 8009

3

Blank page.

4

2

Operation

2.1 Overview

The basic method used to determine resistivity of an insulator sample is a two
step process; first, a test voltage is applied to the sample and the subsequent
current is measured. Then the test voltage value and measured current value are
applied to the appropriate equation, and resistivity is calculated.

The Model 8009 Resistivity Test Fixture is shown in Figure 2-1. The top view
shows th
shows the pushbutton switch that is used to select the desired resistivity test. The
side view shows the test fixture connectors.

The schematic diagram of the Model 8009 Resistivity Test Fixture is shown in
Figure 2-2. Notice that external connection to the electrodes of the test fixture is
accomplished through a 3-lug female triax connector. This connector will mate
directly to the Keithley Instruments Model 6517 using the Model 6517-ILC-3
cable or to a Model 6517B using the Model 6517B-ILC-3 cable.

e inside of

the test fixture where the sample is mounted. The front view

5

Figure 2-1

Model 8009 resistivity test fixture

6

Models 6517 and 6517B Electrometer/High Resistance Meters

Figure 2-2

Model 8009 schematic diagram

The Model 8009 Resistivity Fixture is designed to fully support the enhanced
resistivity measurement capability of the Model 6517 and Model 6517B
Electrometer/High Resistance Meters. Models 6517 and 6517B employ the
ASTM D-257 measurement method, and display measurements in resistance,
surface resistivity, or volume resistivity. All the Model 8009 electrode constants
are programmed into Models 6517 and 6517B. A built-in high voltage source
provides test voltages up to 1000 volts.

Models 6517 and 6517B offer special features for sophisticated, precise
measuremen
measure” sequence in which the test voltage is applied for a programmed time to
permit resistivity to reach equilibrium, after which the measurement can be made
at some desired voltage. Models 6517 and 6517B can also measure and record

t of resistivit

y. Both models can automatically implement a “bias-

7

temperature and relative humidity using a type-K thermocouple (included with

e Model

Model 6517), and the optional Model 6517-RH relative humidity probe.

The information presented in sections 2.2 through 2.8 covers all aspects of opera­tion in detail. Section 2.9 integrates the operating information together to provide
a short, but co

3.3 provides resistivity nomographs that can be used to approximate resistivity.

mprehensive pro

cedure to make resistivity measurements. Section

2.2 ASTM standard

Methods, recommendations and calculations used in this manual to make
resistivity measurements are based on the following ASTM Standard:

American Society for Testing and Materials, S
Test for Electrical Resistance of Insulation Materials, ASTM
Designation D257

tandard Methods of

2.3 Insulator sample mounting

The minimum and maximum sample sizes are listed in the specifications.

NOTE

Do not handle the insulator sample with bare fingers. Body oil
will provide
ment. The use of acetate rayon gloves is recommended. For
best

results, clean the sample surfaces with an alcohol and

r mixture or other suitable solvent.

ethe

Perform the following steps to mount the insulator sample in the Model 8009:

1. The top electrode in the Model 8009 is permanently attached to the t
A test sample is provided with the Model 8009 to protect the

cover.
electrodes (this sample can be used for a functional check of the Model

8009). Remove the test sample. When finished, reinstall the test sample to
protect the electrode surfaces from nicks and scratches.

2. Center the insulator sample between the top and bottom electrodes of the

Mode

l 8009. Make sure

other than those through the sample.

3. Close the lid of the test fixture and secure the latch.

a conductive path and may corrupt the measure-

there are no conductive paths between the electrodes

op

8

2.4 Model 6517 Connections

Figure 2-3

Connecting the Model 6517 Electrometer/High Resistivity Meter to the Model
8009 test fixture

Refer to Figure 2-3 to connect the Model 6517 to the Model 8009 test fixture.
The triax cable and the Model 6517-ILC-3 interlock cable are supplied with the
Model 8009. Note that the ground link on the Model 6517 must be removed.
Proper grounding will be performed by the Model 8009.

2.5 Model 6517B Connections

Refer to Figure 2-4 to connect the Model 6517B to the Model 8009 test fixture.
The triax cable and the 6517B-ILC-3 interlock cable are supplied with the Model

8009. Note that the ground link on the Model 6517B must be removed. Proper
grounding will be performed by the Model 8009.

9

Safety considerations

Model 6517B

6517B-ILC-3 interlock cable

OPTION SLOT

250VDC MAX

MADE IN

U.S.A

LINE RATING

50-60 Hz

100 VA MAX.

LINE

WARNING: NO INTERNAL OPERATOR SERVICABLE PARTS, SERVICE BY QUALIFIED PERSONNEL ONLY.

CAUTION: FOR CONTINUED PROTECTION AGAINST FIRE HAZARD, REPLACE FUSE WITH SAME TYPE AND RATING.

1250Vpk

PREAMP

OUT

1000VDC

MAX

FUSE
630mAT

315mAT

100V
120V
220V
240V

COMMON 2V OUT

LO HI

V SOURCE

TRIGGER LINK RS-232

DIGITAL I/O

HUMIDITY

TEMP

TYPE K

INTERLOCK

IEEE-488

2VDC MAX

Figure 2-4

Connecting the Model 6517B Electrometer/High Resistivity Meter to the
Model 8009 test fixture

The earth ground screw terminal of the Model 8009 Resistivity Test Fixture must
be connected to a known safety earth ground using the Model 8007-GND-3
ground wire, or #18 AWG or larger wire.

The use of hazardous voltage requires that interlock
is activated when
cable (both supplied with the Model 8009) is connected as shown in Figures 2-3
and 2-4. Whenever the lid of the Model 8009 is open, the Model 6517 or Model
6517B will go into standby, thus removing power from the test fixture.

the Model 6517-ILC-3 or the Model 6517B-ILC-3 interlock

be used. The interlock circuit

10

WA

R N IN G

To prevent electrical shock that could
death:

1.

Put the Model 6517 or Model 6517B voltage source in STANDBY
before opening the lid of the Mo

2. Make sure the interlock cable is connected as shown in Figur
(Model 6517) or Figure 2-4 (Model 6517B).

3. Make sure the earth ground screw on the Model 8009 is
connected to a known safety earth ground using the Model
8007-GND-3 or #18 AWG or larger wire.

del 8009.

cause injury or

e 2-3

2.6 Test voltage

Typically specified test voltages to be applied to the insulator sample are 100V,
250V, 500V and 1000V. Higher test voltages are sometimes used, however the
maximum test voltage that may be applied to the Model 8009 is 1000V. The most
frequently used test voltages are 100V and 500V. The Keithley Instruments
Model 6517 can provide test voltages up to 1000V.

2.7 Current measurement range and compliance limit

To make the most accurate resistivity measurement, the Model 6517 must be on
the most sensitive (optimum) current measurement range. The simplest way to
achieve this is by placing the Model 6517 in autorange.

In general, a current compliance limit is to
For virtually all resistivity tests, protecting the insulator sample from excessive
current is not a concern.

If manual ranging must be used, you may have to experiment to determine the
best measurement range and subsequent compliance limit. For
information on compliance and measurement range selecti
6517 or Model 6517B Reference Manuals.

protect the devi

ce under test (DUT).

detailed

on, refer to the Model

2.8 Electrification time

Electrification time is the total time that the specified voltage is applied to the
insulator sample when the current measurement is taken. For example, for an
electrification time of 60 seconds, the current measurement would be taken after
the insulator sample was subjected to the applied voltage for 60 seconds. Keep in
mind that experimentation may dictate a different electrification time. Unless
otherwise specified, an electrification of 60 seconds is recommended.

11

2.9 Resistivity measurement procedure

3

Equations

The previously detailed operating information is integrated into the following
procedure to make resistivity measurements.

WARNING

The following procedure uses haza
cause severe injury or death. Exercise extreme caution
when the voltage source is in operate.

NOTE

To calculate volume resistivity, the average thickness of the
samp

le must b

to measure it. Calipers will provide a precise measurement.

e known. If thickness is not known, use calipers

rdous voltage

that could

1. Mount the insulator sample in the Model 800
for detailed information.

2. Close the lid of the test fixture, secure the latch and
pushbutton switch for the desired test (SURFACE or VOLUME).

3. With power off, connect the test fixture as shown in Figure 2-3 (Model 6517)
or Figure 2-4

To prevent electrical shock that could cause injury or
deat
nected and the Model 8009 earth ground screw is properly
conne

4. While in standby, set the voltage source to the appropriate test voltage.
Typically,

5. While still in standby, set the Model 6517 or 6517B to an appropriate mea­surement range and cu
ance limit will suffice for mo

6. Place the voltage source in operate and after an appropriate electrification
period, record the current reading from
electrification period of 60 seconds is used.

7. Place the voltage source in standby.

(Model 6517B). See sections 2.4 and 2.5 for details.

WARNING

h, make sure that

cted to a safety earth gr

500V is used as the test voltage for insulators.

the interlock cable is properly con-

ound.

rrent compliance limit. Autorange and a high compli-

st tests.

9 test fixture. See

set the RESISTIVITY

the display. Typically, an

paragraph 2.3

12

3.1 Introduction

3

Derivation of Resistivity

Equations

Figure 3-1

Basic measurement techniques

For instruments that do not directly measure resistivity, this section provides the
equations needed to calculate volume and surface resistivity using the applied
test voltage and the measured current. If accuracy is not needed, nomographs (see
figures 3-2 and 3-3) can be used to approximate resistivity. This section also
shows how to derive the equations used to calculate resistivity.

3.2 Calculating resistivity

The following equations used to calculate volume and surface resistivity are
based on the physical dimensions of the electrodes of the Model 8009. Section

3.4, Derivation of Resistivity Equations, explains how these equations are
derived.

13

Volume Resistivity: Volume resistivity is defined as the electrical resistance

ρ

22.9V
t

c

I

---------------ohm-centimeter=

ρ

3.55V
t

i

I

---------------ohm-inches=

σ

53.4V
I

---------------ohms=

through a one-centimeter cube of insulating material and is expressed in ohm­centimeters. Likewise, the electrical resistance through a one-inch cube of
insulating material is expressed as ohm-inches.

Volume resistivity (ρ) is

measured b

y applying a voltage potential across
opposite sides of the insulator sample, measuring the resultant current through
the samp

le (see Figure 3-1), and then performing one of the following

calculations:

or

Where: ρ is the volume resistivity of the sample.

V is

the applied voltage from the Electrometer.

is the average thickness of the sample in centimeters.

t

c

is the average thickness of the sample in inches.

t

i

I is the current reading from the Electrometer.

Surface Resistivity: Surface resistivity is defined as the electrical resistance of
the surface of an insulator material.

It is measured from electrode to electrode
along the surface of the insulator sample. Since surface length is fixed, the
measurement is independent of the physical dimensions (for example, thickness
and diameter) of the insulator sample.

Surface resistivity (σ) is measured by app

a voltage potential across the

lying
surface of the insulator sample, measuring the resultant current, and then
performing the following calculation:

Where: σ is the surface

resistivity

of the sample.
V is the applied voltage from the Electrometer.
I is the current reading from the Electrometer.

14

3.3 Resistivity nomographs

Figure 3-2

Surface resistivity (σ) nomograph

With test voltage and measured current (and sample thickness for volume
resistivity) known, resistivity can be approximated by using the appropriate
nomograph. Figure 3-2 shows the nomograph for surface resistivity and Figure
3-3 shows the nomograph for volume resistivity.

Surface Resistivity: The

surface resistivity nomograph (Figure 3-2) is

made up
of three scales; voltage, resistivity and current. Perform the following steps to
determine resistivity:

1. Plot the test voltage value on the voltage scale.

2. Plot the measure current value on the current scale.

3. Draw

a straight line connecting the plotted vo

ltage and current values.

4. Read the surface resistivity value (in ohms) from where the drawn line inter­sects the resistivity scale.

An example is shown in the graph. The dashed line connects
200V to a measured current of 3 × 10
the resistivity scale at just under 4 × 10

-10

amps (0.3nA). The dashed line intersects

13

¾ (3.56 × 1013¾ by calculation).

a test voltage of

15

Volume Resistivity: The volume resistivity nomograph (Figure 3-3) is made up

Figure 3-3

Volume resistivity (ρ) nomograph

of four scales and a Graph Line. The four scales include; thickness (in cm) and
current. Perform the following steps to determine volume resistivity:

1. Plot the average sample thickness

2. Plot the test

3. Draw a straight

voltage value on the voltage scale.

line connecting the plotted thickness and v

(in cm) on the thickness scale.

oltage values.

Note that this line will intersect the graph line.

4. Plot the measured current value on the current scale.

5. Draw a straight line from where the first

line intersects th

e graph line to the

plotted current value.

6. Read the volume resistivity value (in ohm-cm) from where the second line
intersects the resistivity scale.

An ex

ample is shown on the graph. The first da

ickness of 0.15 cm to a test voltage of 200V. The second dashed line (b)

th
connects the Graph Line intersection point to a measured current of 6 × 10
amps (60pA). The second dashed line (b) intersects the resistivity scale at
approximately 5 × 10

14

¾-cm (5.09 × 1014¾-cm by calculation).

shed line (a) connects a sample

-11

16

3.4 Derivation of resistivity equations

ρ

A

t

----R=

A

D

2

0

4

-------= π

A

2.125()

2

4

-------------------- π 3.55square inches==

A

5.40()

2

4

----------------- π 22.9square centimeters==

The ASTM standard states that volume resistivity (ρ) shall be calculated as
follows:

(Equation 1)

Where: R is the volume resistance in ohms.

t is the average thickness of the sample.
A is the effective area of the guarded electrode for the part

electrode arrangement employed.

icular

For the Model 8009, which uses circular electrodes, A is

(Equation 2)

Where:D

, which is the effective diameter of the guarded electrode (see figure

0

3-4), is 5.40 cm (2.125 in.). Thus,

or

calculated as follows:

17

By using the calculated values for A, volume resistivity (Equation 1) looks like

ρ

22.9
t

c

---------- R=

ρ

3.55
t

i

---------- R=

ρ

22.9V
t

c

I

---------------ohm-centimeter=

ρ

3.55V
tiI

---------------ohm-inches=

σ

P
g

---R=

this:

or

Where: t

is the average thickness of the sample in centimeters.

c

is the average thickness of the sample in inches.

t

i

Volume resistance (R) is derived by dividing the applied test voltage (V) by the
subsequent measured current (I). By substitut
tions that are used in

Section 2 to calculate volume resis

ing R with V/I, the following equa-

tivity are realized:

or

The ASTM standard states that surface resistivity (σ) shall be calculated as
follows:

(Equation 3)

Where: R is the surface resistance in ohms.

g is 0.125 inches. This is the distance between the guarded electrode and

the ring electrode (see Figure 3-4).

P is the effective

perimeter of the guarded electrode for the particular

electrode arrangement employed.

18

For the Mode

σ

2.125π

0.125

-----------------R 53.4R==

σ

53.4V
I

---------------ohms=

Figure 3-4

Electrode dimensions

l 8009, which uses circular electrodes, P

P = D

π

0

is calculated as follows:

Where: D

, which is the effective diameter of the guarded electrode (see Figure

0

3-1), is 2.125 inches. Thus,

P = 2.125π

By substituting the values for g and P into Equation 3, it then looks like this:Sur-

face resistance (R) is derived by dividing the applied test voltage (V) by the sub­sequent measured current
that is used in Section 2 to calculate s

(I). By substituting R with V/I, the following equation

urface resistivity is realized:

19

4

Maintenance

Blank page.

20

4.1 Introduction

4

Maintenance

Normal maintenance for the Model 8009 consists of periodic cleaning of the
electrodes and proper storage to keep the electrode surfaces from getting nicked
and scratched. Also included in this section is a procedure to check out the
operation of a test system, and a parts list.

4.2 Cleaning

The electrodes of the Model 8009 should be periodically cleaned with methanol
or other suitable solvent. The connectors should also be kept clean to prevent
leakage when measuring low level current.

When not in use, keep the supplied test sample installed between
This will help prevent the surfaces of the electrodes from getting nicked and
scratched.

the electrodes.

4.3 Replaceable parts

Table 4-1 lists the replaceable parts that are available for the Model 8009. These
parts can be obtained directly from Keithley Instruments, Inc. When ordering
parts, be sure to indicate the Model number (8009), serial number, and the
Keithley Instruments part number.

The unit can be returned for factory service, if desired. Call the Repair
Department at 1-800-552-1115 for a Return Material Authorization (RMA)
number. When returning the test fixture, write ATTENTION REPAIR
DEPARTMENT on the shipping label, and be sure to advise as to the warranty
status of the unit, as well as the type of service required.

21

Table 4-1

Model 8009 replaceable parts list

Description

Keithley Instruments
Part Number

ASSY, 3LUG TRIAX CABLE
BOTTOM PLATE
BUSHING
6517-ILC-3 CABLE ASSEMBLY
6517B-ILC-3 CABLE ASSEMBLY
CENTER ELECTRODE
COMPRESSION SPRING
COND RUBBER CENTER
COND RUBBER TOP
CONNECTOR TRIAX
CONNECTOR, 4-PIN MALE
CONN, BANANA JACK BLK
CONN, BANANA JACK RED
DRAW LATCH
FOOT, BLACK MOLDED POLY
GROUND STRAP
HANDLE
INSULATOR TEFLON
PLATE BASE
POGO PIN
PUSHBUTTON
RING ELECTRODE
SAMPLE
SILICONE ADHESIVE
SPACER, NYLON
SPACER PLATE
SPRING, LEAF
SWITCH
SWITCH, DOOR INTERLOCK
TEST BOX
TOP PLATE
TOP WEIGHTED ELECTRODE

7078-308-3C
8009-302A
14782G
6517-330A
CA-509A
8009-305A
SP-7-1
8009-307A
8009-308A
CS-630
CS-458
BJ-12-0
BJ-12-2
FA-261
FE-10
8009-318B
HH-29
11647
8008-305B
CS-833
29465-9C
8009-304A
8009-317A
CE-17
15712B
8009-309A
8009-310A
SW-493
SW-486
8009-301B
8009-303A
8009-306A

22

Service Form

Model No. Serial No. Date

Name and Telephone No.

Company

List all control settings, describe problem and check boxes that apply to problem.

 Intermittent  Analog output follows display
 Particular range or function bad; specify:
 IEEE failure  Obvious problem on power-up
 Batteries and fuses are OK  Front panel operational
 All ranges or functions are bad  Checked all cables

Display or output (check one)

 Drifts  Unable to zero
 Unstable  Will not read applied input

 Overload  Calibration only
 Calibration certificiate required  Data required

(attach any additional sheets as

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

Where is the measurement being performed (factory, controlled laboratory, outdoors)?

What power line voltage is used: Ambient temperature: °F

Relative humidity: Other:

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

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

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

necessary)

23