Ac Current, Frequency, Duty Cycle Measurements - Extech Instruments MM750W User Manual

AC CURRENT, FREQUENCY, DUTY CYCLE MEASUREMENTS

CAUTION: Do not make 10A current measurements for longer than 15 seconds;
Exceeding 15 seconds may cause damage to the meter and/or the test leads. Always
turn the meter OFF for 15 minutes before measuring again.
WARNING: Never measure current above 600mA in the µA/mA range and 10A in the
10A range. The voltage in the measurement circuit must not exceed 1000V AC.
1. Insert black test lead banana plug into the negative COM jack.
2. For current measurements up to 6000µA AC, set the function switch to the µA
position and insert the red test lead banana plug into the µA/mA jack.
3. For current measurements up to 600mA AC, set the function switch to the mA
position and insert the red test lead banana plug into the µA/mA jack.
4. For current measurements up to 10A AC, set the function switch to the 10A
position and insert the red test lead banana plug into the 10A jack.
5. Press the M button to indicate
6. Remove power from the circuit under test, then open up the circuit at the point
where you wish to measure current.
7. Touch the black test probe tip to the neutral side of the circuit. Touch the red test
probe tip to the 'hot' side of the circuit.
8. Apply power to the circuit. Read the current in the display.
9. Press the Hz/% button to indicate 'Hz'. Read the frequency on the display.
10. Press the Hz/% button again to indicate '%'. Read the duty cycle on the display.
11. Press the Hz/% button to return to current measurement.
(AC) on the display.
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