Resistance Measurements; Continuity Check; Diode Test - Extech Instruments EX505 User Manual

RESISTANCE MEASUREMENTS

WARNING: To avoid electric shock, disconnect power to the unit under test and discharge all
capacitors before taking any resistance measurements. Remove the batteries and unplug the line
cords.
1. Set the function switch to the ΩCAP
2. Insert the black test lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive Ω jack.
3. Press the MODE button to indicate "Ω" on the display.
4. Touch the test probe tips across the circuit or part under test. It is best to
disconnect one side of the part under test so the rest of the circuit will not
interfere with the resistance reading.
5. Read the resistance in the display.

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 Ω jack.
3. Press the MODE button to indicate"
4. Touch the test probe tips to the circuit or wire you wish to check.
5. If the resistance is less than approximately 100Ω, 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
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.
"and "Ω" on the display
position.
and V on the display.
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