Hewlett-Packard 00974-90002 User Manual

HP 974A Multimeter

User’s Guide

Part Number 00974-90002
March 1995

© Copyright Hewlett-Packard Company 1994, 1995
All Rights Reserved

HP 974A Multimeter

Table of Contents

Safety Summary . . . . . . . . . . . . . . . 1-4

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

Maximum Overvoltage Limitations . . . 1-5

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

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

Terminals, 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

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

Maintenance . . . . . . . . . . . . . . . . . 1-15

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

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

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

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

Replaceable Parts/Accessories . . . . . 1-16

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

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

Declaration of Conformity

1-3

Safety Summary

The CAUTIONS and WARNINGS w hich ap pear on the fol lowing pag es mu st be follow ed to
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 b y the prod uct func tions, rang es, an d haza rds as in dicted below .

2. To minimize poss ible elec tric shock ha zard con dition, co nnect onl y two leads at an y one
time to any of the multimeter terminals.

3. To prevent poss ible elec tric shock ha zard con dition whe n using the current function, do not
leave one probe connected to the circuit under test and the other probe disconnected,
exposed, and rea dily a ccessi ble (touch able ).

Safety Symbols

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

Indicates termina ls at whic h dangerou s voltage s may exist.

WARNING
TO AVOID ELECTRICAL SHOCK or damage to the m ultimet er, do not a pply mor e than

±1000 Vd c or 1000 Vr ms between an y termin al and eart h ground . Use caution when work ing with
voltages abo ve 6 0 Vdc or 4 2 Vpea k. Ens ure test le ads are in go od c ondit ion.

WARNING
POSSIBLE ELE CTRIC AL SHOC K. Do not m ake m eas ureme nts if the case i s dam age d or t he

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

WARNING
POSSIBLE ELECTRICAL SHOCK or FIRE HAZARD. Do not expose this multimeter to rain or

moisture. Do not oper ate the multi meter in the presence of flam mable gas es or fumes.

1-4

Safety Summary

WARNING
POSSIBLE ELE CTRIC AL SHOC K. Ca librat ion a nd p erfo rmanc e test s are to b e pe rform ed by

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

CAUTION

To avoid damage to the multimeter fo r inputs abov e 250 Vdc or Vac, dis connect th e 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 ma ximu m voltag e be tw een i npu t ter mina ls an d ea rt 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 4000 Vpk or an y DCV c ircui t whe re th e ma ximu m imp ulse overvo ltage 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 service pa nel circui ts (CAT III) over 30 0V to earth.

1-5

Safety Summary

Function Maximum Operating Input

10 A

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

Resistance , Di ode Te st,
Temperature, Continuity

Frequency
(10 Hz to 9.999 kHz)
(9 kHz to 200 k Hz)

V

± 10 A (dc or ac rms ) / 600 V

500 V (dc or ac rms)

500 Vrms
100 Vrms

± 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 oth er d amage tha t may r esul t in r educ ed e lectr ic sh ock pr otectio n.

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

3. If probes other than the on es specified are to be used wi th the multi meter, be sure th e

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.

1-6

Operation

Terminals, Shutter, & Test Leads

SAFETY SHUTTE R

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.

RED LEAD

Current Measurements
(0 A to 10 A)

RED LEAD

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

RED LEAD

Current Measurements
(0 to 400 mA)

BLACK LEAD

COMMON
ALL Measurements

1-7

Operation

Function Switc h

Switch

Position

10A

500 mA

50 mA

500 µA

Ω

mV

1-8

Display

DC Current

(1 mA to 10 A)

DC Current

(10 µA to 0.5 A)

DC Current

(1 µA to 0.05 A)

DC Current

(0.01 µA to 0.5 mA)

Diode Test Auto Diode Test
Resistance

( 0.01 Ω to 50 MΩ)

DC Millivolts

(10 µV to 500 mV)

V
V

DC Volts

(100 µV to 1000 V)

AC Volts

(1 mV to 750 V)

1

Voltage and frequency readings alternate on display

AC Curre nt

(1 mA to 10 A)

AC Curre nt

(10 µA to 0.5 A)

AC Curre nt

(1 µA to 0.05 A)

AC Curre nt

(0.01 µA to 0.5 mA)

Continuity

(alarm at < 100 Ω)

AC + DC Volts

(1 mV to 750 V)

Frequency

(10 Hz to 200 kHz)

Temperature in °F
(-112° F to 302° F)

Frequency and Volts

(10 Hz to 200 kHz)

Temperature in °C

(-80° C to 150° C)

1

(-59.94 dBm to 62.22 dBm)

dBm

Operation

Function Key s

Power

Automatic power of f after 30 min utes. Alarm so unds 30 se conds be fore autom atic pow er off.
Press any key or change any function to cancel automatic power off. Defeat automatic power
off by holding key for 2 seconds whil e applyi ng power .

Relative/Percent

Press Action Main Display Secondary Display

Makes the displ ayed mea surem ent

Calculates the percentage change

Cancels the Relative/% function Measurement value Range

Perform a zero adjust when using the 500 Ω range and displayed val ue is less than 99 by shorting the test
leads and pressing this key. Cycle power to erase the stored zero adjustment.

the reference

from the reference

Each measured value relative to

the reference value (difference)

Each measured valu e as a

percent chan ge o f the refere nce

value

Range

Range

1-9