(under subclass 234) Subject matter wherein the input is alternating current and the final control device is a switch which is caused to change to its conductive state at or about the zero axis crossing of the input waveform.
(1) Note. Usually, the average power applied to the load is controlled by varying the number of half or full cycles of input waveform that is permitted to flow to the load.
SEE OR SEARCH THIS CLASS, SUBCLASS:
319, for external or operator controlled systems of this type.
SEE OR SEARCH CLASS
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,
451+, for semiconductor controlled rectifiers which are involved in zero point switching.
