Continuity Check; Diode Test - Extech Instruments 420 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
0V and an open device will indicate "OL" in both polarities.
position.
position.
9 EX420-EU_ENG V3.1 6/09