Hello and welcome,

This is an easy Instructable for adjustable power supply that every electrician must have.

The project is under 10$ but you can scrap or scavenge most parts I used.



I am not responsible if you hurt yourself or others around you!

Step 1: Things You Need

2 x wood pieces 20 x 12 cm / 7.8 x 4.7 inch (free)

2 x wood pieces 11 x 12 cm / 4.3 x 4.7 inch (free)

LM317 Voltage regulator (1-2$), heatsink is optional

4 x 9 Volt battery connectors or you can use banana plugs but battery connectors are cheaper and you can find them for free by scavenging old batteries. (4$ if you buy banana plugs) (2$ if you buy battery connectors or free)

Switch (1$)

10K potentiometer (2.5$)

LED Voltmeter (optional but it's cheap, 1$ on Ebay)

9-24 Volts power adapter or laptop charger (Free or you can buy it for fairly low price)

30μF electrolytic capacitor (20 cent), 10pF ceramic/film capacitor (10 cent), 1kΩ resistor (10 cent).

Hot glue, duct tape

Some wire to connect all, soldering iron and solder.

Step 2: Cut Wood Pieces and Drill Holes

Layout is optional but I found this one is the most practical one.

I used battery connectors all the time like sockets. (Explanation later)

Step 3: Glue It Together and Fill the Holes

I soldered power adapter to another battery connector so I can plug and unplug it whenever I want.

Make sure you glue it very tight.

Step 4: Electronics

I'm sorry I can't show you the whole proces but here is the easy schematic.

You can solder everything on a board, but I found this is easier for me.

You can now add LED voltmeter and solder it (+ goes in the middle pin, - goes to ground)

LED voltmeter measures 4.5 Volts minimal, have that in mind.

Last step is to glue the back panel.

Step 5: Final Product

You can add up to 30 volts power adapter, but be sure to add a heatsink.

And you can put 9 volt battery and use it like mobile power supply.

This is a little project that takes few hours to make.

I hope you enjoyed, leave a comment below if you have any questions.

<p>I connected it to 22V power supply (for my cordless drill) and it's not working with 10K variable resistor? Do I need bigger value of resistor or? </p>
<p>How do you know that resistor is a problem? Can you take some pictures of your soldering and post it here so I can check the problem?</p>
<p>It's on breadboard but it's not about my connections because it does regulate to just 15V.. When I disconnect the potentiometer it's about 22V..</p>
<p>Then you should try 1k or 5k potentiometer. See how that works and let me know.</p>
Why would you need such a big box? It is all empty inside, isn't it? &deg;_&deg;
<p>I wanted it to look big so I can fulfil free space on my workbench. You can make it however you want, it is your choice. Best regards</p>
<p>How can you change the current output? It appears this is only for voltage. Will I have to get a more expensive power board?</p>
<p>For current limiting you will need a different and more complicated circuit. Maybe I will do it in the future. :D</p>
<p>I made a prototype and it's working to 12V, can I connect two adapters for more power? btw. Good Job!</p>
<p>Yes you can, connect them in series. </p><p>Thank you.</p>

About This Instructable




Bio: I am attending the middle school for electrical engineering in Sarajevo. I'm 17 years old teenager with plans to become an electrical engineer.
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