What is the purpose of using a power MOSFET in the main voltage input of a circuit? Why not just directly connect the main voltage input to a power supply? Why go through the MOSFET?
I am trying to understand a circuit that goes directly from a 12V battery to Drain of a P-channel power MOSFET. The Gate is connected to ground through a 1MOhm resistor and connected to Source through a Zener diode. The circuit is connected to the Source pin.