How to distinguish whether the MOS DIODE is N-channel or P-channel

How to distinguish whether the MOS tube is N-channel or P-channel

1. How to determine the three poles of MOS

The identification of the three feet on the mosfet tube symbol should grasp the key points.

G pole, needless to say, is easier to recognize. The S pole, whether it is a P-channel or an N-channel, is where the two lines intersect. The D pole, whether it is a P-channel or an N-channel, is the side of the separate lead.

2. How to distinguish whether the field effect transistor is N-channel or P-channel

Answer: In the circuit diagram, the arrow of the N-channel MOS tube points to the inside, and the arrow of the P-channel points to the outside.

The N-channel measurement method is: turn the multimeter to the diode gear, connect the red test lead to the S pole, and the black test lead to the D pole. If the resistance value of 400 to 800 is measured, it can be judged that the MOS tube is N-channel. The measurement method of p-channel is: turn the multimeter to the diode gear, connect the red test lead to the D pole, and connect the black test lead to the S pole. If the resistance value of 400-800 is measured, it can be judged that the mosfet tube is a p-channel.

(Measure a set of values (600-800) of s pole and D pole with the diode file of the test pen. Red S, black D is N channel, black S, red D is P channel).

3. How to determine the direction of the parasitic diode

Next, it is the direction judgment of the parasitic diode:

Its judgment rule is: N channel, from S pole to D pole; P channel, from D pole to S pole.

Regardless of N-channel or P-channel MOS transistors, the arrow direction of the intermediate substrate and the arrow direction of the parasitic diode are always the same: either all point from S to D, or both point to S from D.