Update: Power supply

Alright so if you made this power supply you probably noticed that it wasn't powering your LED's or motors or whatever. Well the problem is in the last post I said to solder your negative wire to the middle terminal on your potentiometer. You do have to do that but instead of soldering your test wires to the third terminal they actually go to the same one as the negative wire. So move the wires you have on your third terminal to your second terminal and you are good to go.

DIY variable power supply

In this tutorial I will show you how to make a variable power supply. If these instructions aren't explicit enough let me know and I will do my best to fix them and if you have and questions feel free to ask.

Materials:

10k potentiometer.

1k resistor.

330 ohm resistor.

Toggle switch.

lm317T adjustable regulator

LED (color of your choosing).

22 gauge wire.

A nob for the potentiometer.

2 banana plugs (optional).

2 alligator clips.

Project box (size of your choosing).

And last but not least a power supply (you can use a printer power supply, an ATX power supply but for this I am just using a 9v ac power adapter, what this does it takes in however many volts ac and converts it to dc. If you are using the same kind of power supply make sure it converts into dc, also I am using this power supply because when I tested it with my multimeter it said 15v so it has a higher voltage than it says on the adapter).

Tools:

Soldering iron.

Solder.

Wire strippers.

Wire cutters.

Drill and various drill bits.

Philips head screwdrivers.

Helping hands (not necessary but come in handy).

Step one:

Cut the jack off of your power supply.

.

Step two:

Drill holes in your project box, you can arrange them however you want but I did it this way because I thought that is the way it would fit best.

I have a hole drilled on each side and one in the back.

Step three:

Run the wires from your power supply into the hole in the back. And attach a black wire to one of your banana plugs and to your alligator clips, also do the same with a red wire an alligator clip and banana plug. Strip the wires of the power supply and your alligator clips and banana plugs. Now attach your black banana plug and alligator clip wires together, make sure you attach black wire to black wire and red wire to red wire. You don't need the banana plugs but I am putting them in so I can power my breadboard.

Step four:

Get out your lm317 adjustable regulator your wire and your potentiometer. Make sure you attach them the right way here is a schematic to help you out. I found this schematic on this website so they might be able to help you out http://www.rigacci.org/docs/biblio/online/voltreg/fan-regulator/tutorial-full.html.

In case you don't understand this on the lm317T the pins go by name so pin one is adjust pin two is output and pin three is input. And also you might see that he has some capacitors and other resistors, these are not necessary. All they do is help keep the buzzing sound down but this power supply is very quiet so you don't need those.

Now connect your 1k resistor to pins one and two on your regulator.

Also you want to connect the positive wire from your power supply to pin 3 on your regulator.

Connect a wire to pin one on your regulator and attach it to terminal one on your potentiometer.

If you are wondering where the third terminal is on my potentiometer it fell off because I have used it more than once. There is just the little part on the circuit board left of it which I am going to have to solder it to.

Now connect the negative wire on your power supply to your toggle switch.

Also connect a black wire to the cathode (short lead) on your LED, my LED had wires so I twisted the negative wires from my LED and a black wire I cut and soldered them to the second pin on my switch. You are also gonna wanna solder your 330 ohm resistor to the anode (long lead) lead on your LED. Add a wire to the other end of your resistor and attach it to the third lead on your regulator. Plug in your power supply and flip the switch your LED should have power.

Now remember that other wire we attached to the switch? Well that is gonna go to the second terminal on your potentiometer. (These pictures were not taken/posted in order so the wire I attached to the first terminal isn't there right now).

Now run your black alligator and banana plugs through the side hole on the right side of your project box. And also run you red alligator and banana clips through the left side on your project box. Solder your black wires to the third terminal on your potentiometer and the red wires to pin two on your regulator.

Now your done!!! All you have to do is mount it inside your project box and you are finished.