HP 974A User Manual

HP 974A Multimeter

User’s Guide

Part Number 00974-90002
March 1995

HP 974A Multimeter

Table of Contents

Safety Sum mary . . . . . . . . . . . . . . . 1-4

Safety Symbols . . . . . . . . . . . . . . 1-4

Maximum Overvoltage Limitations . . . 1-5

Probes and Test Leads . . . . . . . . . 1-6

Operation . . . . . . . . . . . . . . . . . . . 1-7

Terminal s, Shutter, & Test Leads . . . 1-7

Function Switch . . . . . . . . . . . . . . 1-8

Function Keys . . . . . . . . . . . . . . . 1-9

Function Keys/Function Switch Matrix . . 1 -1 2

Display . . . . . . . . . . . . . . . . . . . 1-13

Audio . . . . . . . . . . . . . . . . . . . . 1-13

Calibration and Adjustment . . . . . . . . 1-14

Required Test Equipment . . . . . . . . 1-14

Calibration Procedure . . . . . . . . . . 1-14

Maintenanc e . . . . . . . . . . . . . . . . . 1-15

Battery Replacement . . . . . . . . . . . 1-15

Fuse Replacement . . . . . . . . . . . . 1-15

Troubleshooting . . . . . . . . . . . . . . 1-16

Cleaning . . . . . . . . . . . . . . . . . . 1-16

Specifications . . . . . . . . . . . . . . . . 1-17

General . . . . . . . . . . . . . . . . . . . 1-17

DC Voltage . . . . . . . . . . . . . . . . . 1-17

AC Voltage . . . . . . . . . . . . . . . . 1-17

AC + DC Voltage . . . . . . . . . . . . . 1-18

DC Current, AC Current . . . . . . . . . 1-18

Resistance . . . . . . . . . . . . . . . . . 1-19

Continuity . . . . . . . . . . . . . . . . . . 1-19

Diode . . . . . . . . . . . . . . . . . . . . 1-19

Frequency (AC Coupled) . . . . . . . . . 1-19

Temperature . . . . . . . . . . . . . . . . 1-20

dBm . . . . . . . . . . . . . . . . . . . . . 1-20

Adjustments . . . . . . . . . . . . . . . . . 6-1

Calibration Table . . . . . . . . . . . . . . . 6-2

Replaceable Parts/Accessories . . . . . . 6-4

Disassembly . . . . . . . . . . . . . . . . 6-5

Declaration of Conformity

Safety Summary

The CAUTIONS and WARNINGS w hich appe ar on the followi ng p ages mu st b e foll owed t o
ensure operator safety and to retain the operating condition of the Multimeter.

1. Do not use this product beyond its specifications or for uses not intended for this product
as identified by th e prod uct fu nctions , rang es, an d ha zard s as i ndicte d be low.

2. To minimize po ssible el ectric shoc k hazard condition , connect on ly two leads at any one
time to any of the multimeter terminals.

3. To prevent po ssible el ectric shoc k hazard condition when using the curre nt function , do not
leave one probe connected to the circuit under test and the other probe disconnected,
exposed, and rea dily acces sible (tou chab le).

Safety Symbols

Indicates the operator must refer to an explanation in this manual.

Indicates term inals at whic h danger ous volta ges may exis t.

WARNING
TO AVOID ELECTRICAL SHOCK or damage to the multi meter, do n ot app ly mor e th an

±100 0 Vdc or 100 0 Vrms betwee n any termi nal and ea rth ground . Use cauti on when wo rking with
voltages a bove 6 0 Vd c or 4 2 Vp eak. E nsure test lead s ar e in good condi tion .

WARNING
POSSIBLE EL ECTR ICAL SH OCK. Do not make meas ureme nts if the case is d amage d or the

rear cover is removed. Remove all electrical inputs before removing the rear cover.

WARNING
POSSIBLE EL ECTR ICAL SH OCK. Ca libr ation and per forma nce te sts ar e to be pe rfor med b y

qualified personnel only. Do not attempt calibration or test procedures unless qualified to do so.

CAUTION

To avoid damage to the multimete r for inputs ab ove 250 Vdc or Vac, disconnec t the test leads
before changing functions. Do not exceed the maximum input limits.

Maximum Overvoltage Limitations (AC and DC Voltage Functions)

1000V
MA X indicates the maxi mu m volt ag e betw ee n inp ut termi na ls an d eart h is ± 1000 V (dc or ac rms).

Do not use the multimeter on any ACV circuit where the maximum impulse overvoltage may
be more tha n 40 00Vpk or a ny D CV circ uit w here t he ma ximu m imp uls e over volta ge ma y be
more than 2500Vpk between the COM and VOLT terminals. Excessive impulse overvoltage
can damage the multimeter voltage functions. Do not measure branch circuits (CAT II) over
600V to earth or servic e panel circ uits (CAT III) over 30 0V to earth.

Safety Summary

Function Maximum Operating Input

10 A

± 10 A (dc or ac rms) / 600 V

mA or µA ± 500 mA (dc or ac rms) / 250 V

Resistan ce, Diod e Te st,
Temperature, Continuity

500 V (dc or ac rms)

Frequency
(10 Hz to 9.999 kHz)
(9 kHz to 2 00 k Hz)

500 Vrms
100 Vrms

V

± 1000 Vdc or 750 Vrms

Probes and Test Leads

1. Always inspect probes before use. Do not use test leads whose insulation has cuts,

cracks, or o ther d ama ge tha t may res ult in red uced elec tric sh ock protec tion.

2. Keep insulation surface clean between the probe tip connector and the finger guards.

3. If probes other than th e ones specif ied are to be use d with the mult imeter, be sure the

probes and their leads are rated for the voltage and current to which they will be subjected.
Do not exceed the voltage ratings for the multimeter.

4. Probes supplied with this multimeter are rated for use up to 1000Vrms or Vdc.

Safety Summary

Operation

Terminals, Shutter, & Test Leads

RED LEAD

Current Measurements
(0 A to 10 A)

RED LEAD

RED LEAD

DC & AC Voltage,
Diode, Resistance,
Frequency, Temperature, dBm
and Continuity Measurements

SAFETY SHUT TER

Slide up to open shutters
for current measurement
inputs. Must have the
function switch in one of
the Current Measurement
positions to open shutter.
Close shutter to change
function switch to any
other measurement
function.

Function Swi tch

Switch

Position

Display

10A

DC Curren t

(1 mA to 10 A)

AC Curr ent

(1 mA to 10 A)

500 mA

DC Curren t

(10 µA to 0.5 A)

AC Curr ent

(10 µA to 0.5 A)

50 mA

DC Curren t

(1 µA to 0.05 A)

AC Curr ent

(1 µA to 0.05 A)

500 µA

DC Curren t

(0.01 µA to 0.5 mA)

AC Curr ent

(0.01 µA to 0.5 mA)

Diode Test Auto Diode Test

Ω

Resistance

( 0.01 Ω to 5 0 M Ω)

Continuity

(alarm at < 100 Ω)

Temperature in °F
(-112° F to 302° F)

Temperature in °C

(-80° C to 150° C)

mV

DC Millivolts

(10 µV to 500 mV)

Operation

Function K eys

Power

Automatic powe r off after 30 min utes. Ala rm sounds 30 second s before aut omatic pow er off.
Press any key or change any function to cancel automatic power off. Defeat automatic power
off by holding key for 2 second s while ap plying power.

Relative/Percent

Press Action Main Display Secondary Display

Makes the dis played m easure ment

the reference

Each measured value relative to

the reference value (difference)

Range

Calculates the percentage change

from the reference

Each measur ed val ue as a

percent chan ge o f the refe rence

value

Range

Cancels the Relative/% function Measurement value Range

Operation