Switching frequency is defined as the rate at which the power transistor is turned ON and OFF.

Fsw: Switching Frequency

Ton: On-time of the power transistor in ms or µs or ns

Toff: Off time of the power transistor in ms or µs or ns 

Ton+Toff =T: It is the switching period of the power transistor in ms or µs or ns

Typically, the switching frequency of power electronic switches can vary from a few kHz to a few MHZ ranges.

Switching frequency of GAN transistor (MHz to GHz) > Silicon MOSFET (MHz) > IGBT (1 KHz to 100 KHz) > GTO (1 KHz)>Thyristors (100 HZ)