MOSFET Transistor and Diode Checks
How-To Check a MOSFET Transistor
- G ==> Gate
- D ==> Drain
- S ==> Source
1: Check that your transistor is not connected to your circuit and turn on the multimeter.
2: Connect the multimeter's negative lead to S. While holding the transistor, be sure to only grip it by its plastic casing so as not to interfere with the reading.
4: Touch the multimeter's positive lead to G to charge the internal capacitor.
5: Move the multimeters's positive lead to D. You should see a low reading (<1 Ohm) on the multimeter. The MOSFET is now "on", as its internal capacitor has been charged.
6: With everything still connected (negative to S & positive to D) touch your finger across all three: G, D, S. You should get a high reading (>50 kOhms). This indicates that the MOSFET is now non-conductive, as the gate has been discharged.
If at any point in the above steps you lose contact between either of the multimeter leads and the transistor, touch your finger across all three pins and start over. If you got through all the steps and got the expected readings then your MOSFET transistor is functioning.
