Variable Power Supply

 by WWC
6.bmp
 This build is for a variable power supply. I have a bench power supply i made from an ATX power supply and it works great but, it is not variable. Sometimes i need 6v or 9v ect. I cant do it with the ATX supply. So i built this one.
It has a dedicated 5V dc supply for logic circuits. Plus a 1.3V dc to 22V dc variable supply. My volt meter only goes to 20V dc so at 22V the meter is pegged clear over. 

The reason some of this is built this way is because i used everything  from my parts on hand, except the 1K 2 Watt resistor. That i had to buy for this project.

Parts:

1)  Lm317 IC
1) .1µf cap Mylar number 104
1) 10µf cap 16v
1) 1µf cap 50v
1) 100 ohm 1/4 Watt resistor Brown Black Brown
1) 220 ohm 1/4 Watt resistor Red Red Brown
1) 1K ohm 2 Watt Resistor Brown Black Red
1) 5K pot. A 2k Would be best
2) 1N4007 Diodes
1) Volt Meter 20V dc
1) DPDT Toggle sw
2) SPST  Toggle sw
1) Power Supply or Transformer 24V out
1) Mounting Board or Project  Box
4 ) Header Pins
?) Various Screws, Wire ect
? ) Stuff i Forgot to list


The LM317 voltage regulator has 3 posts. Looking at it from the front, from left to right its 1 2 3. Post 1 is adjust. Post 2 is V out. Post 3 is ground. Its easy to get them mixed up, so be aware of orientation.  
 
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Step 1: Tools and Be-Careful

There are 4 pictures of things you want to use.

There are 4 pictures of things you dont want to use.

Be-Careful so you can choose the 4 of these you want to use.  

You wouldn't want to be forced to choose the 4 you dont want to use. 
 
                                             !!!      KEEP IT SAFE     !!!
pfred2 says: Apr 5, 2012. 9:22 AM
I made my first LM317 power supply when I was 13. It wasn't pretty, but I was really proud of it.

http://i.imgur.com/Y9BWW.jpg

Extra points if anyone knows what the metal frame was before I salvaged it for my project.
WWC (author) in reply to pfred2Apr 8, 2012. 5:36 AM
I too your quiz about the metal frame. I believe i have flunked. I do not know what that frame is.
pfred2 in reply to WWCApr 8, 2012. 8:35 AM
OK I'll give you a hint. It could have been found in every living room across the USA back in the day.
WWC (author) in reply to pfred2Apr 8, 2012. 8:41 AM
Radio
pfred2 in reply to WWCApr 8, 2012. 1:21 PM
A little too far back, but close! It is a TV tuner knob cage. You know, out of one of those old huge console TVs it used to take two strong men to move around.
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