On Sat, 6 May 2006 14:03:45 +1000, "Peter"
put finger to keyboard and composed:

http://members.ozemail.com.au/~pebar...N3055schem.jpg
A fellow hobbyist told me it was not a good circuit arrangement as it had
poor regulation with the NPN pass transistors. Can someone explain to me
why?

TIA
Peter

Remembering that this is a variable power supply, ie one where the
voltage is trimmed to suit the load, and assuming that the load is
reasonably constant (eg 10 +/- 1 amps), then the regulation error in
this case would be +/- 70mV. This is not too bad at 13.8V, say. OTOH,
a bursty load such as amateur radio equipment will be poorly
regulated. Having said that, I doubt that this would matter much to
most radio hams. In fact a friend had a simple design based on the
same pass transistors and an LM723 regulator IC. The transformer was
massive, though.

- Franc Zabkar
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