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make bench power supply Adjustable Voltage Control?
Ok so i have a atx bench power supply i made and now i need to be able to put a Adjustable Voltage Control dial on it so i can go from 0v to 12v how do i do so? And can i use any spare parts from around the house?
Comments
10 years ago
You need to convert the atx supply as you have already done, and then add another circuit to create a variable voltage. This is easy enough with an adjustable voltage regulator. It works like a 7805 or 7812 regulator but instead of just having in and regulated out, it has in, reference, and regulated adjustable out. The LM317 is a great cheap example: But be advised, it has some drawbacks. Regulating the voltage drops it from anywhere around .3v (high quality digital alternatives) to 2 volts, so the most you can regulate out of 12 volts is 0-10 adjustable.
Search for LM317 circuit to get a schematic -- there are a hundred here on instructables alone.
Answer 3 years ago
what if you use the -12 and +12 to get 24v, for a max of 22v after the drop?
however, i heard the +12v is rated different amperage than the -12v - do you know how to determine the max current draw?