Extech MN42 Operating Manual

User's Guide

Digital Multimeter

Model MN42

Introduction

Congratulations on your purchase of the Extech MN42 MultiMeter. The MN42 offers AC/DC
Voltage, DC Current, and Resistance testing. Proper use and care of this meter will provide
many years of reliable service.

Safety

This symbol adjacent to another symbol, terminal or operating device
indicates that the operator must refer to an explanation in the Operating
Instructions to avoid personal injury or damage to the meter.

WARNING

CAUTION

MAX
600V

SAFETY INSTRUCTIONS

This meter has been designed for safe use, but must be operated with caution. The rules
listed below must be carefully followed for safe operation.

1. NEVER apply voltage or current to the meter that exceeds the specified maximum:

Function Maximum Input

V DC or V AC 600V AC and DC 200Vrms on the 200mV range

mA DC 200mA DC 250V fast acting fuse

ADC 10A 250V fast acting fuse

Resistance, Continuity 250Vrms 15 seconds max

2. USE EXTREME CAUTION when working with high voltages.

3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 500V above

earth ground.

4. NEVER connect the meter leads across a voltage source while the function switch is in

the current, resistance, or diode mode. Doing so can damage the meter.

5. ALWAYS discharge filter capacitors in power supplies and disconnect the power when

making resistance or diode tests.

6. ALWAYS turn off power and disconnect test leads before opening the covers to replace

the fuse or battery.

7. NEVER operate the meter unless the back cover and the battery and fuse covers are in

place and fastened securely.

8. If the equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.

This WARNING symbol indicates a potentially hazardous situation, which
if not avoided, could result in death or serious injury.

This CAUTION symbol indicates a potentially hazardous situation, which
if not avoided, may result damage to the product.

This symbol advises the user that the terminal(s) so marked must not be
connected to a circuit point at which the voltage with respect to earth
ground exceeds 600VAC or VDC.

This symbol adjacent to one or more terminals identifies them as being
associated with ranges that may, in normal use, be subjected to
particularly hazardous voltages. For maximum safety, the meter and its
test leads should not be handled when these terminals are energized.

This symbol indicates that a device is protected throughout by double
insulation or reinforced insulation.

Input Protection Limits

(30 seconds max every 15 minutes)

2

MN42-EU - V1.1 – 07/2010

Controls and Jacks

1. Non-Contact Voltage Sensor

2. LCD Display

3. Function switch

4. Positive jack

5. COM jack

6. 10A jack

Note: Tilt stand, fuse, and battery compartment
are on rear of unit.

Symbols

•))) Continuity

Diode

µ micro (amps)

m milli (volts, amps)

k kilo (ohms)

Ω Ohms

Alternating (AC) current

Direct (DC) current

BAT Battery test

-

+

Low battery icon

1

2

3

4

5

6

3

MN42-EU - V1.1 – 07/2010