Active Device: Silicon Controlled Rectifier

An active device is an electronic component that is capable of controlling the flow of electrons. It requires a source of energy to function and is capable of amplifying signals or switching them on and off. One of the examples of an active device is a Silicon Controlled Rectifier (SCR), which is a type of semiconductor device.

SCR: Definition and Working

SCR is a three-layered device made of P-type and N-type semiconductors. It has a gate, cathode, and anode terminals. The device is turned on by applying a positive voltage to the gate terminal, which allows the current to flow from the anode to the cathode. Once the SCR is turned on, it remains in the on-state until the current flowing through it drops below a certain level.

Applications of SCR

SCR is widely used in various applications, including:

1. Power Control: SCR is used in power control circuits to regulate the amount of power supplied to a load.

2. Motor Control: It is used in motor control circuits to control the speed of the motor.

3. Lighting Control: SCR is used in lighting control circuits to dim the light according to the requirement.

4. Rectification: It is used in rectifier circuits to convert AC voltage into DC voltage.

Conclusion

In conclusion, Silicon Controlled Rectifier (SCR) is an active device that is widely used in various applications. It is a three-layered semiconductor device that can control the flow of electrons in a circuit. SCR is turned on by applying a positive voltage to the gate terminal and remains in the on-state until the current flowing through it drops below a certain level.