Sunday, January 20, 2008

Variable (+/-) DC Supply

I started designing thing with +/- 15V mostly instead of the usual 9 volts I was working with before. I don't have a split supply so i built this simple one. It is variable from about +/- 2 to 18 volts DC.

Its based on the LM337 and 317 of course. The transformer is overkill but the point was to build it out of parts I already had.

The circuit is simple enough to perfboard. It is straight from the application notes (using a 1k pot and an 82 ohm resistor) with 1N4004 diodes protecting the regulator as suggested. The large caps off the transformer are 4700 uF.

There is no display of the output voltage. I monitor it with a multimeter.

Probably not the best supply in the world but more than enough for what I need.

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