How to determine the quality of the FET

The method for determining whether a FET is good or bad is totally different from that of a transistor. The following describes how to determine whether a FET is good or bad: 1. the multimeter is equipped with a diode; 2. the red pen is connected to d pole, and the black pen is connected to S pole. In turn, the quantity is connected to a pressure drop of V; 3. the red pen is connected to the G pole, and the black pen is connected to the S pole, but this step is very important. The G Pole has been charged with a charge, and the tube has been activated; 4. red pen again connects D pole, black pen connects S pole, at this time there should be a pressure drop of a few volts, indicating that the pipe has been activated; 5. the table pen remains unchanged, touch the three poles of the tube with your fingers, discharge between G and S, and shut down the tube. d and S are disconnected again. if the above process is correct, you can confirm that the pipe is good. if it is a P-Channel MOS, replace the multimeter with a red-black table pen.