Neelandan just posted up another great project, a 12v regulator circuit to power things from your PC–
“To safely power something from your PC, the attached loads have to be limited to a safe current in order to avoid the chance that a short circuit might cause inadvertent shutdown and damage to your data. This circuit can be used to safely bring out the 12V line from your computer to supply a limited amount of current to power external gadgets.” – Link.
6 thoughts on “HOW TO – PC Power 12 V regulator circuit”
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This is a voltage regulator circuit, not a current limiter. It relies on voltage sag for current regulation and also uses the highly variable gain of the pass transistor (bad design practice). a better circuit is here
http://tpub.com/neets/book7/27n.htm
updated the post a bit, thanks
This seems… like an odd way of doing it. Very odd indeed. If you wish 12v supply, you can’t really regulate it from 12v. Besides, the 12v coming from the PC supply is already regulated. Every voltage regulator needs at least a little overhead, four or five volts. I’m a little confused as to why this whole circuit can’t be replaced by a single series resistor.