HP 4328A Service Manual

Section I
Paragraphs L-1 to 1-10
SECTION I
GENERAL INFORMATION
1-1. DESCRIPTION
1-2. The Model 4328A Milliohmmeter (Fig. 1-1) is
a portable instrument designed to measure low resist-
ance with speed and accuracy. Covering a resistance
range of. OOH2 to 100!1, the mstrument uses a Kelvin
Bridge method to obtain high sensitivtty Although
the 4 terminal method is used to insure accuracy,
only 2 probes placed on each end of the sample are
used m the actual measurement.
1-3. To avoid measurement errors due to thermal
emfs, contact potential differences and electrolytic
polarization, the measurement utilizes a 1kHz :::ilgnal
and is msensitive to d .. c errors. '
1-4. In the measurement of contact res1stance of
components used in low level s1gnal circuits, swttches.,
relays and connectors, the measurement voltage ap-
plied should be less than 20m V peak so that thm insu-
lating films are protected from breakdown With the
4328A, voltage across samples 1s less than 200t.tV
peak on any range (when proper range setting used).,
and a maximum voltage of 20mV if incorrect range
settings are used.
1-5. The 4328A can be used to measure heat-sensitive
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samples because the power dissipatwn in samples is
very low. Voltage applied to samples is automahcally
llm1ted to permit safe measurement of fuses and ex-
plosives
1-6. A unique phase dLscriminator in the meter cir-
cuit_ insures accurate measurement of samples with
senes reactance up to twLce full scale reststance ..
1-7. 150V superimposed de bias may be present on
samples durmg measurement. Thus, direct measur~
ment oi mcremental resistance of back biased diodes
may be performed, permithng use of the 4328A in the
design of semiconductor circuitry.
1-8.. Complete specifications of the Model4328A are
given in Table 1-1.
1-9.. ACCESSORIES FURNISHED
1-10 Model 16005A Clip-type probe, 16006A Pin-
type probe and 16007A B Test Leads are furnished;
these probes or test leads may be "mtxed or matched"
in any configurahon determined by the form of the
sample to be measured.. Also detachable power cord
is supplied with the .. Model 4328A Milliohmmeter ..
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Figure 1-L Model 4_328A Milliohmmeter
1-1

HP 4328A Specifications

General

Brand	HP
Model	4328A
Category	Measuring Instruments
Language	English