EXTECH EX840 [5/12] Operation

EX840-EU-EN-V5.3-3/12

Operation

NOTES: Read and understand all Warning and Caution statements in this operation manual prior

to using this meter. Set the function select switch to the OFF position when the meter is not in use.

AC Current Measurements

WARNING: Ensure that the test leads are disconnected from the meter before making current

clamp measurements.

1. Set the Function switch to the A

AC or ADC

range

2. Press the trigger to open the jaw. Fully

enclose only one conductor. For optimum

results, center the conductor in the jaw.

3. The clamp meter LCD will display the

reading.

DCA ZERO

The DC Zero feature removes offset values and

improves accuracy for DC current

measurements. To perform a zero, select ADC

and with no conductor in the jaw:

1. Press the DC ZERO button to

zero the display. “ZERO” will appear in the

display. The offset value is now stored andr

emoved from all measurements.

2. To view the stored value, press the DC ZERO button. “ZERO” will flash and the stored value

will be displayed.

3. To exit this mode, press and Hold the ZERO button until “ZERO” is no longer in the display.

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

AC or VDC position.

3. Use the MODE button to select AC or DC Voltage).

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

5. Read the voltage measurement on the LCD display.

Correct

Incorrect