ABSTRACT
One of the most efficient methods of electrical power control is circuit switching. When a switch is turned on, power is consumed by the load device. When a switch in any circuit is turned off, no power is consumed. Lamp brightness is controlled by the switching speed. Power in this method of control is not consumed by the control device. The switching method of electrical power control cannot be achieved effectively with a manual switch. The mechanical action of the switch will permit it to be turned on and off quickly. Electronic switching can be used to achieve the same result. Switching action of this type can be accomplished in a circuit without a noticeable flicker of a lamp. A silicon-controlled rectifier (SCR) is probably the most popular electronic power control device today. The current-voltage characteristics of an SCR tell much about its operation. The triac is the equivalent of two reverse-connected SCRs feeding a common load device.
