This circuit is designed to allow an MCU GPIO to control/drive a high voltage and high current component. The output of the mcu can either be 3 or 5v. The pin is only outputting a very small current.
4 components are needed. Any BJT is good enough. The MOSFET must be powerful enough for the current. Both the MOSFET and BJT must be rated for the max voltage that is on the power supply! In this example, it is 340VDC. If using AC, it must be rectified before feeding it to this circuit.
