Extech Instruments DM220 User Manual

4 DM220-en-US_V3.3 10/20
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 Ω CAP position.
2. Press the MODE button to indicate on the display.
3. 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.
4. 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 position.
2. Press the MODE button to indicate on the display.
3. Touch the test probe tips to the circuit or wire you wish to check.
4. If the resistance is less than approximately 100, 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 position.
2. Press the MODE button to indicate on the display.
3. 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 position.
2. Press the MODE button to indicate nF on the display.
3. Touch the test leads to the capacitor to be tested.
4. Read the capacitance value in the display
FREQUENCY MEASUREMENTS
1. Set the rotary function switch to the V/Hz/% position.
2. Press the Hz /% button to indicate Hz on the display.
3. Touch the test probe tips to the circuit under test.
4. Read the frequency on the display.
% DUTY CYCLE
1. Set the rotary function switch to the V/Hz/% position.
2. Press the Hz/% button to select % on the display.
3. Touch the test probe tips to the circuit under test.
4. Read the % duty cycle on the display.
NON-CONTACT AC VOLTAGE DETECTOR
WARNING: Risk of electrocution. Before use, always test the Voltage Detector on a known live circuit
to verify proper operation.
1. The Voltage Detector works in any function switch position, including OFF.
2. Place the detector probe tip next to the hot conductor or insert into the hot side of the electrical
outlet.

Extech Instruments DM220 Specifications

General

Brand	Extech Instruments
Model	DM220
Category	Multimeter
Language	English