A switch is a component which controls the open-ness or closed-ness of an electric circuit. In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric. Build a one-battery, one- switch, one-lamp circuit as shown in the schematic diagram and in the illustration. This circuit is most impressive when the wires are long.
A switch is an electrical device, usually electromechanical, used to control continuity between two points. Hand switches are actuated by human touch. PNP Relay Switch Circuit The PNP transistor circuit works in opposite to the NPN relay switching circuit. Load current flows from the Emitter to the Collector when the Base is forward biased with a voltage that is more negative than that at the Emitter.