Abstract: A heating pad controller is provided which varies the duty cycle during which power is applied to a heating pad heating element. In one embodiment according to the present invention, an oscillator circuit is used to vary the off-time of the duty cycle, with the on-time portion being fixed. User control of the off-time is provided by way of a rotary control knob connected to a potentiometer. The potentiometer is part of the oscillator circuit and is used to vary the resistance through which a capacitor in the oscillator circuit charges up. The output of the oscillator circuit is used to control the gate of a silicon controlled rectifier (SCR), which acts as a power switch through which power is applied to the heating element. During power up, the oscillator circuit is overridden and a continuous control signal is applied to the SCR to provide constant power to the heating element to thereby achieve rapid heating.