Transistor as a Switch
By As a switch, a transistor can be used to turn on or off a signal.
To use a transistor as a switch, it is typically operated in one of two states: the cutoff state or the saturation state. In the cutoff state, the transistor is effectively turned off and no current flows through the device. In the saturation state, the transistor is effectively turned on and a maximum current flows through the device.
To operate a transistor as a switch, it is typically connected in a common-emitter or common-collector configuration. In a common-emitter configuration, the input signal is applied to the base of the transistor, and the output signal is taken from the collector. When a small input voltage is applied to the base, the transistor turns on and allows a large current to flow from the collector to the emitter. In the cutoff state, the transistor blocks current flow, and no current flows from the collector to the emitter.
In a common-collector configuration, the input signal is applied to the base of the transistor, and the output signal is taken from the emitter. When a small input voltage is applied to the base, the transistor turns off and no current flows from the emitter to the collector. In the saturation state, the transistor allows a maximum current to flow from the emitter to the collector.
