Where do I get...: TV sets
(Links in general lead to photos of the component.)
From color TV sets you can get
- 30kV cascades. They are used to
produce the accelerating voltage for the CRT.
- Flyback transformers 8kV (peak-to-peak) which feed the
cascades. For a photo see 8kV 20kHz transformer (upper left corner of the device).
- in older models: one or two high-power, high-voltage transistors
(e.g BU208) which are also useful for the
8kV 20kHz transformer . They are usually mounted on a large heatsink
close by the flyback and cascade. In newer models, SCR's are
used, which may also be useful.
- If you're lucky, you may find a mains isolation transformer in
older models (I saw exactly one such model up to now :-). However, if
you find a large mains transformer, make sure it's really an isolating
In b/w TV sets or computer monitors you can find
Of course, there's a lot of other useful electronic components in a TV
set, multi-purpose diodes/transistors, voltage regulators, caps,
resistors etc. The CRT may also be of use, see "to do" section. The
flybacks usually take an input of about 700Vpp half-sine-wave pulses
(switched from 150V DC). Always look for a schematic, which may be
attached to the case, it's very useful if you have to find out which
terminals of a flyback you want to use and how the input should look
- instead of a cascade only one hv rectifier (18-20kV). This may be
a solid-state rectifier rod or a vacuum tube , if you've got very old TV.
The vacuum tube is good for generating
- a flyback transformer with 18-20kV output. The rectifier may be
more or less integrated into the flyback (and perhaps cannot be separated).
- high-power, high-voltage transistor(s) as in color
TV's. SCR's are not used. In really old models, there may be a
valve (PL504) instead of the transistor(s).
Remember that the CRT has a sufficient capacity to deliver a nice
little electroshock, even after days. Short the metal parts on the
outside with the hv terminal (look for cable from cascade/flyback) to
[Back to Index]