In this tutorial, we are going to make a 12V 5A Power Supply Using LM338 IC. A power supply is an integral part of any electronic circuit or device, they are used to supply electric power to an electric load.
LM338 is a voltage regulator IC with three terminals, it comes with a lot of built-in features like constant temperature, short circuit protection, thermal regulation, etc. Its voltage is adjustable between 1.2 to 37 volts and you can use it on any desired fixed voltage within its range. This circuit is built to take 12 volts and 5 amperes fixed output from this IC.
Hardware Components
The following components are required to make a 12V Power Supply Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Stepdown Transformer | 230V/15V,5A | 1 |
| 2. | Adjustable Regulator IC | LM338K | 1 |
| 3. | Bridge Rectifier Diode | 10A 50V | 1 |
| 4. | Diode | 1N4007 | 2 |
| 5. | Heat Sink | – | 1 |
| 6. | Resistor | 220Ω, 1.9K | 1,1 |
| 7. | Electrolytic Capacitor | 3300μF, 10μF/25V, 100μF | 1, 1, 1 |
| 8. | Ceramic Capacitor | 0.33μF | 1 |
| 9. | Breadboard | – | 1 |
| 10. | Connecting Wires | – | 1 |
LM338K Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of LM338K
12V Power Supply Circuit
Working Explanation
The transformer is stepping down the voltage from 230V AC to 15V and then it is passed through a 10 Amp 50 PIV bridge rectifier where it’s converted into a DC ripple. This signal is now sent to a noise filtering capacitor before being fed into the IC.
LM338K has three terminals, pin 2 is an input pin where we are sending our DC signal. Adjust pin is Pin 1 which is used to adjust or set the desired voltage, here we have connected it with a 1.9K ohms resistor you can use any other resistor according to your desired output voltage. The output is generated from Pin 3 which is then filtered and sent to the output of this circuit. It’s necessary to use a suitable heatsink because this IC will get hot during the operation.
Applications and Uses
A power supply of 12V is an integral and useful part of Labs because it can be used for a long list of electronic devices and circuits. You can easily build any 12V power supply circuit according to your ampere requirements.
