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