Introduction

A Simple Voltage Regulator is an electronic circuit used to provide a constant and stable output voltage regardless of variations in input voltage or load conditions. Voltage regulators are essential in electronic systems because most electronic components require a fixed voltage to operate safely and efficiently.

This project demonstrates how a stable DC voltage can be obtained using basic electronic components.

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Objective of the Project

The main objectives of this project are:

• To convert an unregulated DC voltage into a regulated DC voltage.
• To protect electronic components from voltage fluctuations.
• To understand the working of linear voltage regulators.
• To design a basic power regulation circuit.

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Working Principle

The voltage regulator works on the principle of voltage stabilization.

Basic Working

1. AC voltage is stepped down using a transformer.
2. The AC voltage is converted to DC using a bridge rectifier.
3. A capacitor filters the ripples from the DC voltage.
4. A voltage regulator IC (such as 7805) maintains a constant output voltage.

The regulator IC automatically adjusts its internal resistance to keep the output voltage stable even if the input voltage changes.

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Components Required

• Step-down Transformer (230V AC to 9V–12V AC)
• Bridge Rectifier (Diodes or IC)
• Filter Capacitor (1000µF)
• Voltage Regulator IC (7805 / 7812)
• Capacitors (0.1µF, 10µF)
• LED (Power Indicator)
• Resistor (220Ω)
• Breadboard / PCB
• Connecting Wires

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Circuit Diagram

Simple Voltage Regulator Circuit (Using 7805)

AC Mains
   |
Transformer
   |
Bridge Rectifier
   |
Filter Capacitor
   |
IN --- 7805 --- OUT ---- +5V DC
        |
       GND

Pin Configuration of 7805

Pin 1: Input
Pin 2: Ground
Pin 3: Output (5V)

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Circuit Explanation

• The transformer reduces high-voltage AC to low-voltage AC.
• The bridge rectifier converts AC to DC.
• The capacitor smoothens the DC voltage.
• The 7805 IC regulates the voltage and provides a constant 5V output.
• An LED indicates the presence of output power.

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Advantages

• Simple and reliable circuit
• Stable output voltage
• Protects electronic components
• Low cost
• Easy to assemble

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Applications

• Power supply for microcontrollers (Arduino, ESP)
• Electronic circuits and projects
• Battery chargers
• Embedded systems
• Laboratory power supplies

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Limitations

• Power loss in the form of heat
• Not suitable for high-current applications without heat sink
• Less efficient compared to switching regulators

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Conclusion

The Simple Voltage Regulator is a fundamental electronics project that plays a critical role in almost every electronic system. It ensures safe and stable operation of circuits by providing a constant voltage supply. This project is ideal for beginners and serves as a foundation for designing advanced power supply systems.