Abstract: A controller for slot cars on either or both domestic and/or commercial track. A programmable pulse width modulation circuit, using at least one integrated circuit to produce an output of variable duty cycle, is provided. This modulation circuit drives transistorized power switches to deliver a DC pulsation of same duty cycle as that of the modulator. The duty cycle is programmed with the use of a simple resistive network array mounted on a small board designed to plug into the rest of the device. Full power bypassing the modulator, transistorized power switches, and filter with another alternative, regenerative braking, are additional features. This controller is revolutionary in design replacing the old wire-wound power resistor technology with modern electronic technology offering the advantages of cool efficient operation and full programmability to match any slot car motor, track, or user.