Oh, one thing I forgot to include:
a lot of the incoming power in that 30V AC has to be
thrown away, in
producing +5V.
So, if my understanding is correct, the 'switching' H744 really isn't much
better than a classic linear supply. It still wastes a very large amount of
the input power, and it still has a massively heavy transformer in it. Yes?
So I wonder what exactly the advantage was in going to the switching approach?
Yes, it keeps the output voltage steadier then a pure linear supply could -
but I'll bet there are analog approaches that can do the same. (They'd need
something that can produce a steady reference voltage, but the switching
approach needs, and has, the same thing.) Maybe the main output transistors
are happier being full-on or full-off, or something like that?
Noel