How to Build a 12V Regulated Power Supply Circuit

Imagine all the cool electronic devices you use need clean, steady power to work right.

That is what a stable power supply does.

This article shows you how to build a simple power supply using a part called a zener diode.

This kind of supply is good for projects that need a constant 12V and can handle a decent amount of power.

What is a 12V Regulated Power Supply Circuit:

A 12V regulated power supply circuit is an electronic circuit that converts an input voltage which can vary to a stable and regulated output voltage of 12V.

This type of circuit is commonly used to power various electronic devices and components that require a stable and reliable source of 12V DC power.

The regulation ensures that the output voltage remains constant even when the input voltage or load conditions change.

Circuit Description

Component List:

The key component in this circuit is the Zener diode, which operates in the Zener breakdown region when in reverse bias.

The Zener diode provides a reference voltage and the transistor Q1 function as a variable resistor with its resistance varying with the base current.

The regulated output voltage (Vout) can be calculated using the following formula:

V_out = V_z − V_BE

where:

• Vout is the regulated output voltage.
• Vz is the Zener voltage.
• VBE is the base emitter voltage of the transistor.

The formula is essential for comprehending the voltage relationship in circuits using transistors or other components where the base emitter voltage drop VBE affects the output voltage Vout.

It is crucial for circuit analysis and design, particularly for uses where exact voltage levels are important.

Advantages and Disadvantages

Advantages:

• Simple and cost effective voltage regulation method.
• Stable output voltage.
• Suitable for high current draw applications.

Disadvantages:

• Limited to low to medium power applications.
• Efficiency may be lower compared to other voltage regulation methods.

Construction Details:

Begin by obtaining at least 15V AC input using a step down transformer.

Convert the AC supply into DC by employing a bridge rectifier module or four 1N4007 diodes arranged in a bridge configuration.

The DC supply is then filtered using a capacitor C1 to smoothen the voltage.

An LED can be included to indicate the presence of the power supply.

To provide the VBC supply to transistor Q1 connect a series combination of resistor R3 and capacitor C2 between the positive and negative supply lines.

Transistor Q1 base terminal is connected to a reverse biased 12V Zener diode ZD1.

ZD1 ensures a constant voltage Zener breakdown at the transistors base, which is responsible for the regulated output voltage.

By changing the Zener diodes rating different output voltage levels can be achieved catering to various application requirements.

Components Working

Zener Diode ZD1

• Provides the reference voltage Vz for the circuit.
• Operates in the Zener breakdown region.
• Acts as a key element for stable voltage regulation.

Transistor Q1 – TIP35C

• NPN bipolar junction transistor BJT.
• Designed for general purpose amplifier and switching applications.
• Low power dissipation and high current capability.
• Suitable for medium power applications.
• Comes in a TO220 plastic package for efficient heat dissipation and ease of handling.

Conclusion

The 12V Regulated Power Supply Circuit using a Zener Diode offers a best and cost effective solution for achieving stable voltage regulation in electronic circuits.

By understanding the principles involved and following the construction guide, you can tailor this circuit to meet your specific voltage requirements.

It is essential to choose the appropriate Zener diode and transistor components to ensure the desired output voltage and current handling capacity.

While this circuit is suitable for various application, it is important to consider its limitations in terms of power output and efficiency for more demanding projects.

Reference:

Regulated Power Supply