Georgia Institute of Technology HP34401A User Manual - User Manual

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GEORGIA INSTITUTE OF TECHNOLOGY

User’s Guide

HP34401A

Digital Multimeter

Brian Brown

Table of Contents

Introduction

Features

Specifications

S E C T I O N 1
Setting Up the HP34401A

Overview of the Controls

S E C T I O N 2
How To Measure DC/AC Voltage

How To Measure DC/AC Current

How To Measure Resistance

How To Measure Frequency

S E C T I O N 3
Trouble Shooting

Where to Find More Help

References

G E T T I N G S T A R T E D

Introduction to the
HP34401A Digital Multimeter

The following is a brief overview of the DMM.

his manual was written to instruct ECE 3041 students on the operation and uses of
the HP34401A Digital Mulitmeter. The HP34401A is a very versatile instrument

capable of measuring numerous circuit characteristics. It is capable of measuring
electric characteristics such as: voltage, current, frequency and resistance with very

high accuracy. These functions will be the focus of this manual. The following guide is for
course-specific applications and not intended to be used as a complete user’s manual. To find

more information beyond the scope of this manual, check the “Where to Find More Help”
section.

Features

he HP34401A is setup for bench-top use with AC power supply. It performs at 1000
readings/sec and has a 6½-digit display. The HP34401A will automatically adjust the

range to the characteristic being measured. It is also extremely accurate: 0.0015%
error for DC, 0.06% for AC.

Specifications

Function

Range

(For accuracy specifications, consult the full manual)

DC Characteristics:

DC Voltage Range and input Resistances:

0.1V, 1V, 10V: input resistance selectable 10MW or > 10GW

100mV to 1000V: Rin = 10MW

DC Current range and shunt resistance:

10mA, 100mA: Rshunt= 5 W

1A and 3A: 0.1 W

AC Characteristics: true RMS:

AC Voltage: from 3 Hz to 300 kHz

AC Current from 3 Hz to 5 kHz

Resistance range: 2-wire and 4-wire

method:

100 W, 1 kW, 10 kW, 100 kW, 1 MW and 100 MW

Input protection: 1000V

Frequency and Period measurement:

Frequency range: 3 Hz - 300 kHz

Input voltage range: 100 mV to 750 V

Table 1

. Table of Function Ranges [1]

G E T T I N G S T A R T E D

Setting Up the HP34401A

1. Get all lab supplies ready for use.

HP34401A Digital Multimeter

Probes Leads (found hanging in wall racks)

Alligator Clips for Lead ends

Breadboard and circuit components (if needed)

2. Turn on the Multimeter.

The front panel display will light up while the meter performs the power-on self –test. After
this is complete, the HP34401A is ready to perform measurements.

Overview of Controls

The front panel has two rows of keys for selecting the functions. The right side of the panel

contains various probe input locations of which the selection is dependent upon the
characteristic being measure (Figure 1). The selection keys are annotated in black and blue. To

select a function in blue, first select the blue

SHIFT

key.

Section

Function Button Panel: DC V or I, AC V or
I, Resistance (ohm’s) and Freq

Probe Input Panel

Power
Button

Figure 1

. Overview of front panel [1]

T A K I N G M E A S U R E M E N T S

Figure 3

. Probe/Meter placement

on the circuit to Measure Voltage

Across Resistor R

Circuit under Test

DMM

How to Measure DC and AC
Voltage

To measure a voltage, connect the probes to the

and

input terminals of the DMM. In

order to activate the DMM for voltage measurements, select either the

AC V

DC V

button

on the front panel (Figure 2).

Next, connect the leads of the probes to
the circuit in parallel with the location of

the voltage in question (Figure 3). The

lead connects to the “+” (pos) part of

the circuit and the

to the “–“ (neg). If

these are reversed, a negative value for the

voltage is obtained.

CAUTION

Do not exceed the maximum allowable voltage input (1000V DC). Also,

never apply a voltage over the current input terminal (I) of the DMM.

Section

FUNCTION

MATH

DISPLAY

DC I

AC I

Ω

Period

dBm

DC V

AC V

Ω

Freq

Cont

Null

Min/Max

Ω

4W Sense

Shift

Select DC V or AC V

AC or Dc Voltage

Figure 2

. How to Measure Voltage

T A K I N G M E A S U R E M E N T S

FUNCTION

MATH

DISPLAY

DC I

AC I

Ω

Period

dBm

DC V

AC V

Ω

Freq

Cont

Null

Min/Max

Ω

4W Sense

Shift

First Shift, then Select
AC or DC

AC or DC Current

Figure 5

. Probe/Meter Placement to

Measure Current Through Meter

Circuit

Under Test

DMM

How to Measure DC and AC
Current

To use the DMM as an ammeter, connect the leads in which the current flows to the current
(

) and

terminals (Figure 4). To measure the current, either the

DC I

AC I

key must be

selected by pushing

SHIFT

and

DC V

AC V

button.

Next, connect the leads of the probes to the
circuit in series with the location of the

current in question (Figure 5). The current
(

) lead connects to the “+” (pos) part of

the circuit and the

to the “–“ (neg). If

these are reversed, a negative value for the

current is obtained.

CAUTION

Do not exceed the maximum allowable current input

(3A DC). Never apply a voltage over the current input terminal

(I)

the DMM. This will cause a large current to flow through the small
input resistor r

and can damage the DMM.

Figure 4

. How to Measure Current

T A K I N G M E A S U R E M E N T S

How to Measure Resistance

To use the DMM for resistance measurements, connect the resistor to the terminals labeled

Ω)

and

, select the resistance measurement function by pushing the

[

Ω

]

button on the

front panel as shown below in Figure 6.

Then connect the leads of the probes to the circuit in
parallel with the resistance in question (Figure 7).

How to Measure Frequency

To use the DMM for frequency measurements, connect to the terminals labeled

HI (V

Ω)

and

. Select the frequency measurement function by pushing the

Freq

button on the front

panel as shown below in Figure 8. The meter is connected in parallel the same as taking a

resistance measurement (Figure 7).

Figure 6

. How to Measure Resistance

Figure 7

. Probe/Meter Placement to

Measure Resistance Across Resistor R

Ω

DMM

FUNCTION

MATH

DISPLAY

DC I

AC I

Ω

Period

dBm

DC V

AC V

Ω

Freq

Cont

Null

Min/Ma
x

Ω

Shif

Select for Frequency
Measurements

Frequency

Figure 8

. How to Measure Frequency

FUNCTION

MATH

DISPLAY

DC I

AC I

Ω

Period

dBm

DC V

AC V

Ω

Freq

Cont

Null

Min/Max

Ω

4W Sense

Shift

Select for Resistive measurements

S U P P L E M E N T A L I N F O R M A T I O N

Troubleshooting

What if the meter will not turn on?

First make sure it’s plugged in; if this is the case get a TA for assistance, the

meter may have a blown fuse or need repair.

The meter is on, but is not taking any readings when it’s connected to the circuit.

Make sure to check that the probe inputs have been inserted in the proper configuration, for
this check back in the “Making Measurements, Section 2” (Notice: voltage and current are

different).

Next, check to make sure that the Front/Rear input selection button is not depressed (located

in the probe input panel to left of the “current (

)” input.

The probe inputs are correct, but when the meter is connected to the circuit the meter reads invalid values or does

not read at all.

Check that the meter is connected to the circuit in the correct orientation. It must be

connected in series for current readings and in parallel for voltage, frequency and resistance.
Check back in the “Making Measurements, Section 2” for more information.

Where to Find More Help

The complete manual on the HP website:

http://www.tm.agilent.com/classes/MasterServlet?view=HomePage&language=eng&locale=
US

The Lab Manual

Lab TA

References

[1]

“HP 34401A user’s manual,” [Online document], Feb. 1996, Available HTTP:

http://cp.tm.agilent.com/data/downloads/eng/tmo/manuals/

pdf/34401A_UsersGuide_English.pdf

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