The conduction condition of the P-channel enhancement type FET is that the gate potential is lower than the drain potential.

The further the gate potential is lower than the drain potential, the more it tends to conduct. Generally lower than the drain potential 15V can be fully turned on. If the voltage difference is too large, gate breakdown will occur. To turn off, pull the gate potential back to the drain.

The junction field effect transistor has only (depletion type); the MOS tube has (enhancement type) and (depletion type).

Enhancement type: There is no conductive channel between the drain and source when UGS=0V, and a conductive channel may appear only when UGS> turn-on voltage (N-channel) or UGS< turn-on voltage (P-channel).

Depletion mode: When UGS=0V, there is a conductive channel between the drain and the source.

Field effect transistors are divided into N-channel and P-channel. What are their turn-on conditions?

They all rely on adding a trigger voltage to the G pole to make the N pole and D pole conduct. The voltage to the N-channel G-pole is + polarity. The G-pole voltage to the P-channel is - polarity. 1. For the motherboard, the commonly used field tubes are 3055, 15n03, 45n03, 60n03, and 70n03 2, 3. To put it simply, the black test lead is connected to the d pole, the red test lead is connected to the s pole, there is a resistance value of about 500 ohms. 4. As for the replacement, the n groove is replaced by the n groove, the p groove is replaced by the p groove, and it is best to use the same model or a higher power to replace (generally, the basic spare for repairing the motherboard is the 60n03 model)