EXTECH MA150 User Guide

User’s Guide

Model MA150
200A AC Mini Clamp-on Meter

Introduction

Congratulations on your purchase of Extech’s MA150 AC Mini Clamp Meter. This meter is shipped
fully tested and calibrated and, with proper use, will provide years of reliable service.

Meter Description

1. Current sense jaw

2. Non-contact AC voltage indicator light

3. Flashlight button

4. Rotary function switch

5. MAX hold and Backlight key

6. LCD display

7. Clamp trigger

8. MODE key

9. COM input jack

10. V Ω input jack

9

10

Safety Information

!

Caution! Refer to the explanation in this Manual

Double Insulation

This meter has been designed to be safe in use, but the operator must use caution in its operation.
The rules listed below should be carefully followed for safe operation.

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

2. USE EXTREME CAUTION when working with voltages greater than 60VDC or 25VAC rms.
These voltages are considerd a shock hazard.

3. NEVER operate the meter unless the back cover and the battery/fuse door are in place and
fastened securely.

Function Maximum Input

AC Current 200A
AC/DC Voltage 600V AC/DC
Resistance, Diode, Continuity Test 600V AC/DC

Input Limits

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Operation

AC Current Measurements

1) Set the Function switch to the 200A AC range.

2) Press the jaw trigger and clamp around, fully enclosing a single conductor.
Do not allow a gap between the two halves of the jaw. Refer to the diagram
at right for the correct way to enclose a single conductor.

3) Read the ACA value on the LCD.

AC/DC Voltage Measurements

1) Insert the black test lead into the negative COM terminal and the red test lead into the positive V
terminal.

2) Set the function switch to the V position.

3) Select AC or DC with the MODE button.

4) Connect the test leads in parallel to the circuit under test.

5) Read the voltage measurement on the LCD display.

Resistance and Continuity Measurements

1) Insert the black test lead into the negative COM terminal and the red test lead into the positive V

Ω terminal.

2) Set the function switch to the Ω position.

3) Use the MODE button to select resistance. The MΩ icon will appear in the display.

4) Touch the test leads across the circuit or component under test. It is best to disconnect one side
of the device under test so the rest of the circuit will not interfere with the resistance reading.

5) For Resistance tests, read the resistance on the LCD display

6) For Continuity, use the MODE button to select continuity “•)))”. The display icons will change
when the MODE button is pressed.

7) If the resistance is <120 Ω  a tone will sound.

Diode Test

1) Insert the black test lead banana plug into the negative COM jack and the red test lead banana
plug into the positive V Ω jack.

2) Set the function switch to the Ω position.

3) Press the MODE button to indicate on the display.

4) Touch the test probes to the diode under test. Forward voltage will typically indicate 0.400 to

0.700V. Reverse voltage will indicate “OL”. Shorted devices will indicate near 0V and an open
device will indicate “OL” in both polarities.

Yes

No

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