Transistor as a voltage regulator

Transistors can be used as series pass and shunt regulators to control voltage and provide a stable output voltage in electronic circuits. Let's explore both configurations:



1. Series Pass Regulator:


In a series pass regulator, the transistor is placed in series with the load, and it controls the current passing through it to regulate the output voltage. There are two main types of series pass regulators: emitter followers and voltage divider bias configurations.


Emitter Follower (Common Collector) Configuration: In this configuration, an NPN transistor is commonly used. The input voltage is connected to the base of the transistor through a voltage divider network (typically resistors). The output voltage is taken from the emitter of the transistor.


When the input voltage increases, the base-emitter voltage also increases, causing the transistor to conduct more current.


This, in turn, increases the current through the load and stabilizes the output voltage.


When the input voltage decreases, the transistor conducts less current, reducing the load current and maintaining the output voltage.


2. Shunt Regulator:


In a shunt regulator, the transistor is connected in parallel (shunt) with the load, and it shunts excess current to maintain a constant voltage across the load. Shunt regulators are also known as voltage reference or voltage regulator diodes.


Zener Diode as a Shunt Regulator: Although a Zener diode is commonly used as a shunt regulator, it is essentially a specialized semiconductor junction diode that operates in the breakdown region. It maintains a nearly constant voltage across its terminals, acting as a voltage reference.


When the input voltage exceeds the Zener voltage (breakdown voltage), the diode starts conducting, shunting excess current to ground.
This keeps the output voltage across the load relatively constant.
Transistor-Based Shunt Regulator: Instead of a Zener diode, a transistor can also be configured as a shunt regulator. In this setup, the transistor conducts current between its collector and emitter terminals to maintain a constant voltage across the load.


The base-emitter junction of the transistor is forward-biased, and it regulates the voltage across the load.
Both series pass and shunt regulators have their advantages and are used in different applications. Series pass regulators are more common when precise voltage regulation and lower power dissipation are required, while shunt regulators are used when a stable reference voltage is needed, often with a higher current-handling capacity. The choice between them depends on the specific requirements of the circuit and the desired performance characteristics. #regulators #shuntregulator #seriespassregulator #electricalcircuits ‪@EasySkill‬




You can follow me on Facebook: https://www.facebook.com/profile.php?...
Face book page:
https://www.facebook.com/infopanel4u?...
Instagram : https://instagram.com/muhammadibrahim...
Contact Email: [email protected]