Hi in this instructable I'll show you that how can you make a variable 12v power supply, that can be used to design electronics projects or as a project power supply. The device is based on the LM2596 NC Voltage Switching Regulator, that is a very effective integrated circuit. I bought mine from Amazon with a voltage display. It's easy, and very glad to use. All link appears in the "Parts" step. Of course you can use this circuit for battery charging, powering up an electronicts project. I think every hobbyist needs a lab bench power supply, but I'm usually using Arduino for my project and I don't work with more then 12 volts, so I don't want to buy an expensive lab bench power supply. That's why I made this cheap and simple power supply. For me cost only 8 bucks because I should buy only the main circuit that was 7.99 dollars. But almost every hobbyist has the other parts in his inventory.

It's easy to use there are four buttons:

if you press "+" the voltage will increase with 0.1 volt, if you press and hold the voltage increases with 1 volt
if you press "-" the voltege decreases with 0.1 volt...
if you press "I" the build in voltmeter measures the input voltage
if you press "O" the voltmeter measures the regulated output voltage

The maximum current of this circuit is 2A, this is more then enough to power up Arduinos. It's simply amazing! Now let's see what else will you need!

Step 1: Parts and Tools

Tools:

Soldering Iron
Glue Gun
Wire Cutter/Stripper

Parts:

DC 12v adapter
2 male and 2 female DC power barrel jack
the LM2596 NC Voltage Switching Regulator
a plastic sheet
2 crocodile clips (black and red)

Step 2: Step 1

Use your soldering iron and and solder one short and one longer wire to the DC barrel input jacks. Usually the positive pin is on right and the negative is on the left (look at the 3rd image).

Step 3: Step 2

You should use agian your soldering iron to solder the crocodile clips to the DC barrel jack. If you want you can connect the crocodile clips directly to your circuit, but I think this is a better solution.

Step 4: Step 3

Use your srewdriver and connect the cables to the circuit.

Step 5: A Quick Test

Power up the circuit and try it out. Mine works fine.

Step 6: Step 4

Now you are close to finish this project, just glue the parts on a plastic sheet just like me. Well, you can make a better case, but isn't neccesary. I wanted to make this gadget portable, this is very important for me. When I'm working with Arduino I need sometimes a small and portable power supply.