The function of MOS transistor in switching circuit

The function of MOS transistor in the switching circuit is the conversion of the signal and the on-off of the control circuit.
Metal oxide semiconductor field effect (MOS) transistors can be divided into two categories: n-channel and P-channel. P-channel silicon MOS field effect transistors have two P + regions on N-type silicon substrates, which are called source and drain. There is no conductance between the two electrodes. When enough positive voltage is added to the source (gate grounding), the N-type silicon under the gate presents a P-type inversion layer, which becomes the channel connecting the source and drain. Changing the gate voltage can change the hole density in the channel, thus changing the channel resistance. This kind of MOS field effect transistor is called P channel enhanced field effect transistor. In the circuit of the N-channel MOS diodee, the BEEP pin can be turned on at a high level, the buzzer makes a sound, and the buzzer is turned off at a low level; the MOS diodee of the P channel is used to control the power on and off of the GPS module, the GPS_PWR pin is turned on at low level, the GPS module is supplied normally, and the GPS module is powered off in high power times.