13 Sep
2005
13 Sep
'05
12:35 p.m.
woodelf wrote:
If this is just to power the nixie tubes, then the current required is
pretty low. You would probably manage it with a mains transformer used
backwards, running off the logic supply transeformer :
Suppose the logic supply transformer has a 9V secondary. Get another,
smaller power, mains-to-9V transformer (say use 50VA for the first one,
20VA for the second, those are likely to be overkill). Connect the
'secondary') of the second, smaller, transformer to the secondary of the
first one (which still supplies the logic PSU circuit). That second
transformer will acts aas a step-up transformer, and will give you
something a bit less than mains voltage across what was originally its
primary winding. And of course that's totally isolated from the mains.
If you manage to get a transformer designed for 230V mains for the second
one (or one with 2 115V 'primaries' that you can connect in series), then
just rectiying it would probably be OK for the nixie tube supply. If you
can only get one with a single 115V primary, you could use a voltage
doubled rectifier. Either way you'll end up with something over 300V DC
-tony
I would have updated the high voltage power
supply to a simple
transistor regulator. I have about 128 AC around here and that
can really give over voltage on 115 V transformers.
PS. Where do you find a 300 V transformer ... I may build one
some day.
If you don't want to scrounge surplus stores, or wind your own, Hammond
currently makes a couple that would work. They are the 269BX and
369BX, depending on whether you want "universal" primaries or not.
Their high voltage secondaries are 300VCT, and they also have the 6.3V
windings. They're a bit larger than necessary, being rated for 2-3
times the power called for in that design.