Ian Stirling wrote in message ...
NT wrote...

OK, the factors stated above do not ensure no 50Hz current is present.
snip
With such a setup, if one emitter has total failure, the tube can
conduct current one way only, giving intolerably strong 50Hz flicker.

No, it can't.

An electronic ballast has a rectifier at the front of it.
The waveform after the rectifier is NOT a 50Hz sine wave.

I'd have to draw the cct and label the waveforms, and I'm too busy
today. I could sit here and assure you it can flicker at 50Hz, but
that wont convince either of us. Maybe if I get the time later I'll
draw it and we'll see what comes up.


Regards, NT