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Radio Shack 3.3V Regulator |
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Written by Nat'n
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Thursday, 20 March 2008 |
 I was planning on playing with my XBee modules this past weekend when I relaized that I did not have any unused 3.3V regulators lying about. Since I needed a regulator to breadboard my design, I ran to Radio Shack. Radio shack seems to be stuck in 1989 as far as components are concerned, and they certianly don't have a very wide selection of in stock components. Well there was no way I was going to wait for mail order so I had to make due with what I had lying about and what I could get at Radio Shack. I bought a LM317T adjustable voltage regulator and combined it with some components I already had and constructed a fairly convienent adjustable voltage regulator with a wide input range (~2-40V) and a reasonable output range (~1.4V to 6.45V).
I basically just replicated the application schematic from the LM317T datasheet ona small piece of perfboard using some very ugly looking point to point soldering. I added a pair of screw terminals for input and a 2+2 right angle male header to the edge of the perfboard. I used a 1K 15 turn trimmer for the variable resistor. I could have used a 5K to get full range output from the regulator, but I only really need 3.3 and 5V output anyway and the smaller trimmer gives me a little more fine control. I had to do a little carving to get everything to fit properly, but it ended up being very compact and functional. I used a 2 x 2 header for added stability when plugged directly into the breadboard and protected the mess of solder and leads on the back side with a layer of ShapeLock to prevent against accidental damage and short circuits. I might make another one later, but now I am thinking of reconfiguring the schematic to make a constant current source to drive serial LED arrays for yet another project I am thinking about. 
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Last Updated ( Thursday, 20 March 2008 )
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