A device used in resistance welding for adjusting the heating value (rms value) of current, and controlling the firing or ignition of the electronic circuit. The control uses vacuum tubes (in older systems) or solid-state devices (e.g., SCRs). The flow of current
is initiated each half-cycle at an adjustable time (or firing angle) with respect to the zero point on the voltage wave. See ELECTRONIC CONTROLS, Resistance Welding.
