Roderick Stewart writes:

In article , Mark Carver wrote:
In the late sixties I worked with a BBC Electronic Services engineer who
regularly used to check whether EHT was present on a faulty monitor by
removing the plug from the tube and sticking his thumb on it.

My grandfather's Christmas party piece was to open up the tin box that
housed the EHT rectifier, and with a damp wooden handle screwdriver,
draw an arc from the anode terminal.

I remember one of those translucent orange handled screwdrivers would do
quite well too. I've no idea what the resistance of the handle would be, but
I'd trust it to be a bit more consistent than a wooden spoon.

Slightly safer now of course, though not quite so much fun, because voltage
triplers are the usual thing - not such a big spark.

The anode terminal of the HV rectifier tube was connected to the flyback
which was 15.7 kHz AC - similar to the output from a small Tesla
coil. So, as long as the screwdriver had some capacitance, the conductivity
of the handle probably didn't matter much.

With modern flybacks, the output is DC filtered by the CRT capacitance,
so the effects are quite different.

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