24 Dec
2007
24 Dec
'07
12:58 a.m.
No, you still need the anode resistor. That's a
current limiting resistor. It's purpose is to prevent
Rememebr that most glow discharges have a negative resistance. They will
'run away' if you don't include the limiting reisstor until the current
gets so high that the tube explodes (literally!).
Remember, you don't need any fancy power IC's
or DC-DC
converters - you can just rectify line voltage (an
isolation transformer is good if you do this...) and
I would never recoemnd running an experimental circuit straight from the
mains without isolation.
Another useful trick (if your PSU already incorporates a normal mains
transdormer) is to connect a small mains transformer of the same nominal
voltage 'backwards' to the secodnary of the PSU transformer. That is, if
you have a mains-9V trasnformer in the PSU anyway, get a small 9V mains
transformer and connect the 9V winding (originally the secondary) to the
secondary of the pSU transformer. You now have an isolated supply of
about mains voltage, from what was originally the primary of that little
transformer.
-tony