Some people have queried me on how to build a regulator. This is a cool
little regulator that is both simple to build, and quite robust.
Some notes:
R7 is listed as a 10K pot -- this pot adjusts the voltage from about
1.5 volts up to whatever the input is. I use a 10 turn pot so that the
adjustment isn't too sensitive.
C1 and C2 should be mounted close to Q1-Q4 for best results.
U1 should be a LM317K in a T03 case. This package is supposed to be
thermal sensitive, and should shut down the regulator if it gets too hot.
U1 should be surrounded by Q1-Q4 on a heatsink in order to keep the
temperature of all five components the same.
Either mount Q1-Q4 and U1 on a real big heatsink, or use a heatsink with
a fan. When it's cutting the power down a lot, it can get quite hot.
This circuit was originally designed to handle 20 amperes, but it should
be able to handle quite a bit more than that now. Tthe transistors in this
version are rated at 15 amperes each. The original design used different
transistors which really sucked and kept on blowing up. If you do want it
to handle lots more current, tweak R1-R4 in relation to R5 so that the
transistors take more load -- they currently need only be around 12 watts, so
there's a bit of overhead to play with. Just make sure the LM317 doesn't
take more than 1 amp or so. Anyway, it works just grand like it is at 20
amperes, and my transformer can't put out any more than that, so I'm happy.
You can email me here for more info
or suggestions.