Intro: Nice Bench Power Supply
0-12 Volts 7 Amps Bench Power suply<br />This is the power supply I have been using for most of my projects since 2009.
it was made for less than 300,- DKR (which is about 50 USD or 40 EUR)
It was as simple and fun to make as it is for me to use today.
You don't have to know a lot about electricity to make this work.
It is capable of giving out 12 volts DC and receiving 8 amps. but depending on the parts you use you can get a device capable of higher amps and possibly higher voltage.
I used the folowing parts:
1.* Old computer power supply salvaged from a thrown out computer -price: (free)
1.* Small DC Motor Speed Control (PWM Controller) picked up at Ebay -about 16-20 USD
1.* Panel volt meter ( not displaying much more than the output of the power supply for better accuracy if a moving needle meter is chosen ) -price about 6-10 USD
1.* Panel Amp meter. -price about 6-10 USD
4.* Rubber feet for furniture. -price about 5 USD
5.* wood plates for front, top, bottom and both of the sides. price ranging from free to about 20.- USD custom pre cut at your local hardware store
6.* Aluminium ventilation grill for the back side. -free to about 8 USD
2.* Contacts with two "on" and one "off" position. -free from salvage to about 10 USD new at some expensive place.
1.* Output plug for voltage output. I got mine from an old radios loudspeaker line out.
1.* sheet of a nice wood sort you like to cover the finished box in. I choose teak. about 3-5 USD for one M4
1.* optional handle for carrying the thing around. salvaged for free or bought new for up to about 10- USD
Step 1: Planing, Finding Stuff and Planing Some More
After making some blueprints of how I wanted my Power supply to look and work, I started to search for the materials around my workshop, and in my garage and I got hold of the wood I needed from a local retail DIY shop. Some shops even cuts out the wood in the dimensions you need and pretty acurate aswell.
For my blueprint i just made a 3 dimentional box with space around the powersupply to alow heat to escape aswell as to fit wires and the voltage controll pcb. Also the front aswell as the depth must acomodate the zise of the panel meters, potmeter, contacts and the outlet sockets.
I made a switch to reverse the polarity on mine as i often work with modet trains and small electric motors.
I also made a switch for bypasing the voltage controller if i want to remove its interferance.
But the choice as for what functions you need is up to you if you wish to create one.
Step 2: The Box Comes Together.
Now I have just put the wood together to see how it will look.
I have not glued, nailed or screwed anything yet. This is just to see if i would need to change something in the last moment
The drawings on the front plate marks where I want the meters and contacts to be.
At the next picture I have drilled the holes for the instrumentation.
After all that was done I put the sides top and bottom together with glue and screws. I did not fasten the front plate, as it is tucked ½ cm into the box it would be easier to aply the fine teak veneer if I could take it out.
Regarding how presed the veneer to the box while the glue hardens by using books, i would personaly recomend you to do it some other way, I had a fight keeping the veneer from rinkeling as it expanded from the wet glue and lifted the weights of the books.
I would recomend using or building some sort of big clamp or workshop press, that or to use a contact glue and a rollto aply it.
Step 3: Ready for Varnish.
The day after: As all the veneer is properly aplied and the glue has had its time to set, it is now time to ad varnish, or perhaps some pigment prior to that if you wish a diferent tone or colour to be added to the wood.
But before the Varnish small mistakes can be corected with glue, sandpaper and small pieces of Veneer.
Now is also the time for cutting the holes to the instrumentation through the veneer.
Step 4: Putting It All Together.
Another day has gone and the Varnish has dryed, now the box has that beautifull shiny teak colour.
I put it all together remembering to conect the Voltmeter in Paralell and the Ampmeter in series. And to put them so that they measure the power after it has been through the power regulator. The potmeter that came with the power regulator is turned up and down to see the voltage change on the voltmeter. if everything works it goes in the box. then the contacts the outlet terminals and are wired and put to the test.
Eventualy everything is working and the unit is almost complete.
Now the PC power suply and the voltage controller PCB is screwed in place.
But the back is still open and must be sealed off without blocking from the circulation of the cooling fan.
I did that with an aluminum grill,
you can also see the rubber feet being mounted.
Step 5: Finished and Ready for Use
Now it is done and ready for use.
As this build is actually about 3 years old by now I can say that I have used it alot on everything from small experiments to testing components on my electric car convertion and manny more.
I am glad to have this usefull powersuply at hand when I need it.
I will upload some better pictures of it later.
There is only one small picky improvement that I would like to make in the near future and that is to replace the tiny voltage controll knob with a cool chickin head knob.
Thanks for watching
I hope you enjoyed