The switching frequency refers to the rate at which the DC voltage is turned on and off during the pulse width modulation process in the 277vac class 2 power supply.

The switching frequency in the inverter is the rate at which the switching device turns on and off. The typical frequency ranges from a few KHz to a few MHz. The increased switching frequency not only reduces the space requirements of the circuit board and enclosure, but also reduces the size of related components (such as inductors, triac led transformer, resistors and capacitors).

A sine wave or is usually used to convert the rectified or battery DC voltage to a higher frequency. In the use of higher frequency 24 volt outdoor power supply, PWM or PFM controllers can be used to adjust how MOSFETs, power transistors or thyristors are turned on and off by oscillator signals. Pulse width modulation (PWM) modifies the duty cycle of a fixed switching frequency to control the time the device stays on or off.

Pulse frequency modulation (PFM) adjusts the variable switching frequency to control the number of times the device is turned on and off. PFM has a constant on and off time. The two modulations are usually used for square wave switching signals, which are easier to filter and adjust than sine waves.