30kV TV-cascade
Color TVs usually contain a 3-stage cascade in a plastic housing to
produce the accelerating voltage for the picture tube. They give
27-30kV dc when fed with an input voltage of about 8kV (peak-to-peak).
If you've got the type as shown, connect your input to (~), ground to
(e1) and expect the output on (hv out) (the thickly insulated lead). Don't
connect (e2), it will short-circuit your ac
source. There's a similar type around, but with these two cables
swapped, so check this out if it doesn't work. On some cascades, (e1)
is labeled "A" and (e2) "D". The additional solder-tag (not labeled
in the above image) gives the output of the first stage (i.e. about
8kV). For a circuit diagram
see 80kV super cascade. As ac input
source you could use an oil burner ignition
transformer or, better, the 8kV 20kHz
flyback supply.
These
things are easy to get, relatively harmless and widely usable for a
lot of experiments. Also, they are the components of the super-cascade
described below, so go and get a bunch of these :-)
HINTS: That end of the hv cable that's plugged into the CRT contains a
current-limiting resistor, so it's advisable to leave the whole cable
untouched. Discharging the cascade without this or a similar resisitor
(some kOhm) will sooner or later destroy it.
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Jochen
Kronjaeger
Kronjaeg@stud-mailer.uni-marburg.de