How to test MOSFET with multimeter
Multimeter use how to test MOSFET with Digital Multimeter and Analog MultimeterMOSFET TESTING Mosfet working principle is input voltage control output current , we can use basic bias to test whether it is a bad or good mosfet . Mosfet has Gate Drain and source legs , take part number to find leg function from datasheet then connect test leads as photo. Note analog multimeter on this testing when set to resistor test function or Ohmmeter , the black test lead supply V+ and the red test lead supply V- ; the reason is the black test lead is connected with positive polarity of internal battery and the red test lead is connected with negative polarity of internal battery. If you are unsure about polarity of your multimeter test leads , you can check it with multimer manual or ask the multimeter expert.
|HOW TO TEST MOSFET|
|Connection diagram to test MOSFET with Analog Multimeter.|
1. Set analog multimeter to Rx10K as this range the multimeter will supply 9VDC from internal battery. 9VDC is high enough to bias gate leg so mosfet is working as ON state.
2. Discharge mosfet by shorting or connecting 3 leg together by using resistor's leg. then do not touch the legs.
3. Connect test leads with mosfet leg as photo above
4. Use resistor's leg to temporarily connect between G leg and D leg ; the pointer of multimeter move to indicate some resistance on ohm's scale as photo.
5. After removing resistor's leg from mosfet's leg the pointer can hold the same position.