"G" wrote in message
...
Howdy Dave......I like your simple solution to use a 7915 from your junk
box and in the process, simplifying your circuitry a little! Of course
my first choice would have been something like a 7912 with a single gen
purpose diode (1N4001 etc) inserted in the leg to ground to bump the reg
voltage output up nearer to 13. With your 7915 you could likewise add a
couple of similar diodes in series with the output to lower the voltage
to your load.

Keep on tinkering.

I'd like to go the diode route as they are more readily available than any
particular transistor. How would I wire them up as relates to my 7915 to
drop (actually raise) the voltage by 2V to -13VDC?

Each diode has a voltage drop and I just string 'em together to add up to
2VDC and tie them from the output of the 7915 to ground? I always figured a
diode was like a one-way resistor. Could I just use a resistor to ground to
get rid of some of my voltage? And, if so, how do I size it if I don't know
my current through the circuit? (I can't measure it, the transistor is
dead). Trial and error is a laborious process.

How can a diode RAISE the voltage of a 7912 (I'll dig around, might have one
somewhere)? Thanks a lot and pardon my ignorance.

Dave



Gord