5V/12V DC Voltage Regulator

5V/12V DC Voltage Regulator For ELV Projects

Introduction

This simple project explains how to build a voltage regulaor circuit using LM7805 & LM7812 ICs.

With Arduino,we mostly use 5V rated components(sensors/relays/solenoids/motors/GSM modules..etc).

But when there is a higher voltage requirement, we have to look for a additional power supply unit.

By using a ATX PSU which can be found in desktop computer systems, we can obtain 12VDC,5VDC & 3.3VDC with higher current ratings.

But if you are looking for a inexpensive alternative and have a extra step down transformer with secondary voltage rating of 14V or higher, You can try this circuit to obtain regulated 12VDC/5VDC voltage with 1A rating.

Why Regulated Voltage?

The reason to use regulated voltage supplies are to protect the load from sudden voltage fluctuations and supply a constant voltage level.

LM78xx series ICs output a constant voltage level despite of the input voltage.

However the energy cannot be created or destroyed.Hence when a higher voltage is converted into a constant voltage level by the IC,the wasted energy is dissipated as heat.

When the input voltage is higher, the heat dissipation will also be high.

Hence this is not a very efficient way of regulating voltage.

However it is the most common and inexpensive method to get a constant voltage level which is being used by many users due to it's simplicity.

Before using this circuit, the input voltage must be converted into DC.

Use bridge rectifier circuit for AC to DC conversion.

Tools & Components

1 X LM7805 IC

1 X LM7812 IC

1 X 0.22uF Capacitor

2 X 0.1uF Capacitor

1 X 0.33uF Capacitor

1 X 2200uF Capacitor

4 X 1N4007 Diodes

1 X 14~35VAC(Secondary) Transformer

2 X Hetsinks

Jumper Wires

Connecting Components

Converting AC to DC

5V /12V DC Regulator Circuit

U1 = LM7812

U2 = LM7805

C1 = 0.1uF

C2 = 0.1uF

C3 = 0.22

C4 = 0.33uF

Side View

Top View

Back View

Note : LM7805 & LM7812 ICs are subjected to higher temperature when it is in operation.Hence use suitable heatsinks to avoid auto shutdown. 

Safety First !

Always Connect the power supply if you are absolutely sure that the components are connected correctly without changing polarity and short circuited the wiring.

Even if it seems nothing is wrong : DOUBLE CHECK EVERYTHING !!

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