Extech Instruments MA220 User Manual page 7

Diode Test
1. Turn the rotary switch to the
2. Insert the black test lead banana plug into the negative (COM) jack and the red test lead
banana plug into the positive (VΩ) jack.
3. Push the mode button to indicate
4. Touch the test probes to the diode under test. Typically for a normal diode, forward
voltage will indicate 0.4V to 0.7V. 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 electrical 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 function switch to the
2. Push the mode button to indicate nF on the display.
3. Insert the black lead banana plug into the negative (COM) jack and
insert the red test lead banana plug into the positive (VΩTemp) jack.
4. Press the ZERO key to null the meter display.
5. Touch the test probe tips to the capacitor you wish to check.
6. Read the capacitance value on the display.
Frequency or % Duty Cycle Measurements
1. Turn the rotary switch to the Volts Hz % position.
2. Insert the black test lead banana plug into the negative (COM) jack and the red test lead
banana plug into the positive (VΩ) jack.
3. Select Hz or % with the HZ/% button.
4. Touch the test probe tips to the circuit under test.
5. Read the frequency on the display.
Ω
•))) CAP position.
on the display.
Ω
•))) CAP position.
7 MA220 V1.3 10/06