DIY Variable Power Supply Using LM317

Power Supply one of the most important tools a tinker can have. It allows us to easily test prototype circuits without having to make a permanent supply for it. it allows us to test circuits in a safe way as some power supplies have features such as over current protection, short circuit protection and many more! But a power supply can get expensive really quick and for beginners investing in something so expensive is not an option. Fear not i'm here today to teach you on how to make an easy lab bench power supply that is easy and beginner friendly to make. Using the LM317T linear voltage transistor!

As this is a beginners project most people will have the materials we need already at home! This materials can easily be salvageable from old computer power supply such as the transformer

Here is the list of the materials

> Transformer (any transformer can be used but mine is a 24V 3 amp one)

> PCB (its the white one in the pic which has a Photoresist layer but you can use ordinary pcb's)

> LM317T (1pcs)

> 5k ohm potentiometer.

> Potentiometer knob

> wires

> ac plug (I salvaged mine)

> electrolytic Capacitor (any value I used 47μF)

> Diodes (1N4001) (4pcs)

> Switch

> 220v led (depends on your region's mains voltage) (optional)

We are going to make 2 pcb's for this project 1 is the FULL BRIDGE RECTIFIER!!!! and the LM317T circuit.

The full bridge rectifier is the one that will turn our ac voltage from the transformer to usable DC voltage to power our circuits.

The LM317T circuit on the other hand is the one that will be regulating and adjusting the voltage going to the circuit.

(In the pictures I showed an example PCB design that you can use)

Whether you etched your PCB or printed unto it its time to etch!

Using the Ferric Chloride place it into a plastic container where you can dip your PCB and etch away the excess copper (Warning: Be careful Ferric Chloride stains clothes and trust me once its stains it stays there forever!)

Follow the schematic Diagram above to place your parts in the correct order!

TIP: Remember to always double check before soldering it will make your life a whole lot easier!

(If you followed my PCB just follow the parts placement above)

Wiring it up is as easy as connecting positive to positive and negative to negative!

Tip: take your time in wire management it's easier to debug if there are problems in the wiring.

In the transformer be careful to wire it up to the correct voltage like for example 0-220V for my region it changes on what country you live in

Great Job!

You can improve upon this project by adding voltage and current monitors, Heat sinks, and Many more!

I hope this project will serve and aid you for years as a thinker!