Continuity Check; Diode Test; Capacitance Measurements - Extech Instruments EX420-NIST 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 green
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 SELECT button to indicate 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 150, the audible signal will
sound. If the circuit is open, the display will indicate "OL".

DIODE TEST

1. Set the function switch to the green
2. Insert the black test lead banana plug into the negative COM
jack and the red test lead banana plug into the positive
diode jack.
3. Press the SELECT 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
and an open device will indicate "OL" in both polarities.

CAPACITANCE MEASUREMENTS

WARNING: To avoid electric shock, disconnect power to the
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 green
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive
3. Touch the test leads to the capacitor to be tested.
4. Read the capacitance value in the display
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