MOSFET Transistor and Diode Checks

How-To Check a MOSFET Transistor

Note: G --> Gate D --> Drain S --> Source

1: Ensure that your transistor is not connected to your circuit and turn on your multimeter

2: Connect your multimeter's negative lead to S

3: While holding the transistor, only ever touch the plastic casing

4: Touch the multimeter's positive lead to G

5: Move the multimeters's positive lead to D and you should get a low reading (<1 Ohm)

6: With everything still connected (negative to S & positive to D) touch your finger across all three: G, D, S and you should get a high reading (>50 kOhms)

If at any point in the above steps you lost 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.