Usual Suspect wrote:
I want to build a bench power supply, and am looking 'round the net
for a good circuit.

Requirements: 2 outputs, adjustable v, adjustable i, v & i meters (or
digits). Prefer 30v max, or similar. Preset v selections (5, 12, 15,
etc.) would be nice.

ok as far as it goes but you need to specify a current, line regulation,
load regulation, curent limiting, crowbar protection,
switching or linear, and even line voltage. also voltage range i.e. 0-30
5 - 30 etc.


Here's one I found, complete with the designer's smiling face on each
circuit illustration:

http://members.shaw.ca/roma/supply-4.html

What's your favorite circuit? Features you like that I haven't
mentioned?

Thanks,

my favorite? that would be 7 or 8 200w or larger NPN transistors in parallel
with emitter resistors mounted on a huge heatsink driven by another 200 W
transistor powered by a very large transformer into matched 30A bridge
rectifiers.
the main filer cap is a very large "computer" cap (ok, if you are young
think of a "power stiffener" for car audio.)

the voltmeter is a large mirrored scale and "expanded" using switchable
precision zeners. i.e. 0-10, 10-20, 20 -30V
the ammeter is a matching large mirrored scale attached to a high current
meter shunt through a multi-turn calibration pot. the meter has diode
limiters to protect it from surges.

the supply can be driven from an internal or external reference. the
reference source is on a separate winding and is offset several volts below
common so as to achieve a zero volt output. for improved load regulation the
regulator references to the output terminals. voltage is controlled via a
multi-turn pot.

primarily intended for high current applications at 13.8 Vdc this unit was
result after many less robust supplies became shall we say... non
functional.