Transistor as an Automatic Switch - Sound Controlled Switch

Sound Controlled Switch

1. Figure above shows the circuit design of a sound controlled switch.
2. The microphone is used to convert sound to electric current.
3. The variable resistor is adjusted as such that the transistor is switched on when sound is detected by the microphone.
4. The function of the capacitor is to prevent the direct current from the cell to flow in the base circuit.