On Wed, 5 Feb 2003 13:15:08 EST MorgusMagnificen@aol.com writes:
> Interesting that this recent discussion of filament supply regulation
is
> taking place at exactly the same time that I have a new amp project
under
> way. When I went to the parts cupboard for a filament transformer, the
> cupboard was bare! So rather than go out and actually buy a transformer
(it
> is mind boggling how much those have escalated in cost) I have decided
to
> build an electronic regulator and use a non-standard low voltage
transformer.
> I will use a full-wave triac bridge with a zero-crossing integral cycle
duty
> cycle controller for virtually noiseless switching.
Hi Eric,
Just a suggestion...
I have an old article (Power Conversion & Intelligent Motion, May
1988, pp76-78) that details a "linear" regulator for a similar
application. It has a diode bridge circuit connected in series with the
primary of the transformer with a transistor connected across that
bridge. The control circuit is built around a dual op-amp.
The application shown was for regulating a 220V line at the 1KW level.
Claimed 4% regulation over that range.
I don't have a scanner but, if you are interested, and can't run the
article down, send me an SASE and I'll Xerox (well... actually Sharp) it
for you.
73 & Good evening,
Marv WC6W 310 649 3111
*
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