Continuity Check; Diode Test; Capacitance Measurements - Extech Instruments MG300 User Manual

CONTINUITY CHECK

WARNING: To avoid electric shock, never measure continuity on circuits or wires that have
voltage on them.
1. Set the function switch to the Ω CAP
2. Insert the black lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive  jack.
3. Press the MODE button to indicate" " and "Ω" on the display
4. Touch the test probe tips to the circuit or wire you wish to check.
5. If the resistance is less than approximately 35, the audible signal will sound.
If the circuit is open, the display will indicate "OL".

DIODE TEST

1. Set the function switch to the Ω CAP
2. Insert the black test lead banana plug into the negative COM jack and the red
test lead banana plug into the positive V jack.
3. Press the MODE button to indicate " " and "V" 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.

CAPACITANCE MEASUREMENTS

WARNING: To avoid electric shock, disconnect power to the unit under test and discharge all
capacitors before taking any capacitance measurements. Remove the batteries and unplug the
line cords.
1. Set the rotary function switch to the Ω CAP
2. Insert the black test lead banana plug into the negative COM jack.
3. Insert the red test lead banana plug into the positive V jack.
4. Press the MODE button to indicate "F"
5. Touch the test leads to the capacitor to be tested.
6. Read the capacitance value in the display
position.
position.
position.
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