Mastech MAS345 User Manual

OPERATOR’S

• AUTO-RANGE

• DUAL DISPLAY

• CONFORMED IEC1010

DIGITAL MULTIMETER

INSTRUCTION MANUAL

CONTENTS PAGE

SAFETY INFORMATION ….……………….…………………………………………...
DESCRIPTION …….………….…………………………………………………………
OPERATING INSTRUCTION ..…………………………………………………………
SPECIFICATIONS ………….…...………………………………………………………
ACCESSORIES ………….………………………………………………………………
BATTERY AND FUSE REPLACEMENT ……………...………………………………

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5
10
17
26
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1. SAFETY INFORMATION

The meter has been designed according to IEC-1010 concerning electronic measuring
instruments with an overvoltage category (CAT II) and pollution 2.
Follow all safety and operating instructions to ensure that the meter is used safely and is
kept in good operating condition.

1.1 PRELIMINARY

·

When using the meter, the user must observe all normal safety rules concerning :

-Protection against the dangers of electrical current.

-Protection of the meter against misuse.

Full compliance with safety standards can be guaranteed only if used with test

·

leads supplied. If necessary, they must be replaced with the same model or same

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electric ratings. Measuring leads must be in good condition.

1.2 DURING USE

·

Never exceed the protection limit values indicated in specifications for each range
of measurement.
When the meter is linked to a measurement circuit, do not touch unused terminals.

·

When the value scale to be measured is unknown beforehand, set the range

·

selector at the highest position.
Before rotating the range selector to change functions, disconnect test leads from

·

the circuit under test.
When carrying out measurements on TV or switching power circuits, always

·

remember that there may be high amplitude voltage pulses at test points, which

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can damage the meter.
Never perform resistance measurements on live circuits.

·

Always is careful when working with voltages above 60V dc or 30V ac rms. Keep

·

fingers behind the probe barriers while measuring.

1.3 SYMBOLS
Important safety information, refer to the operating manual.
Dangerous voltage may be present.
Earth ground.
Double insulation (Protection class II).

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1.4 MAINTENANCE

·

Before opening the meter, always disconnect test leads from all sources of electric
current.
For continue protection against fire, replace fuse only with the specified voltage

·

and current ratings:
F 15A/250V
If any faults or abnormalities are observed, the meter can not be used any more

·

and it has to be checked out.
Never use the meter unless the back cover is in place and fastened fully.

·

To clean the meter, use a damp cloth and mild detergent only, do not use

·

abrasives of solvents on it.

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2. DESCRIPTION

This meter is an autoranging professional measuring instrument. Digit reading is 3999
counts and the bar graph consists of 38 segments for LCD, capable of performing
functions:

-DC voltage measuring (Auto Ranging)

-AC voltage measuring (Auto Ranging)

-DC current measuring

-AC current measuring

-Temperature measuring

-Resistance measuring (Auto Ranging)

-Capacitance measuring

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-Diode testing

-Transistor testing

-Audible continuity testing

2.1 ON/OFF SWITCH

A push − push switch is used to turn the meter on or off. When the switch is push the
beeper will sound.

2.2 DC/AC OR Ω /

BUTTON
This button is used to select DCV or ACV on voltage range, DCA or ACA on current
range, Ω or

on Ω / range. When the button is push the beeper will sound.

2.3 R-H BUTTON
In auto-range, press this button to select manual range and “R-H” symbol will appear on

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the LCD. Press the button again for more than 1 second will come back the auto-range
mode.
When the R-H button is pushed, voltage ranges will change as:

4V → 40V → 400V → 1000V

Or resistance ranges change as:

40MΩ → 4MΩ → 400kΩ → 40kΩ → 4kΩ → 400Ω

2.4 B/L BUTTON
Press this button to toggle back-lit ON. The screen of the meter will light. Press the
button again, back-lit turn off.

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2.5 INPUT JACKS
This meter has four input jacks that are protected against overload to the limits. During
use, connect the black test lead to the COM jack and the red test lead as shown below:

FUNCTION RED LEAD CONNECTION INPUT LIMITS

DCV/ACV

Ω

mA

10A

V/Ω
V/Ω
V/Ω

mA

10A

1000V dc or 750V rms ac

250V dc or rms ac
250V dc or rms ac

400mA dc or rms ac

10A dc or rms ac

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