[Prev][Next][Index][Thread]
Ignitron Tubes
>From what little I understand about ignitrons, they are
a bit like a controllable mercury arc rectifier - ie
what SCR's are to diodes.
Could you use two of them, one between the transformer
and the pulse cap and the other between the cap and TC
primary, ie
Ignitron 1 Ignitron 2
3|E-------(===)----------(===)-----3
3|E | | | 3
3|E gate? --- gate? 3 TC Primary
3|E --- 3
3|E | 3
3|E--------------------------------3
and control the ignitrons so that you charge the cap
up to peak voltage on one half cycle (at 50/60 Hz it
should block and act as a 1/2 wave rectifier.
Once the voltage has fallen, fire the second tube to
connect the primary across the cap. The oscillations
would then continue until there is no energy in the
primary circuit. With all the sparks, the oscillations
should damp quickly and avoid latching in the Low
Frequency HT.
If they are slow to de ionise, won't they still
conduct? May want to add another tube across the
second back to front and trigger them together.
Then fire the first ignitron again and start the
cycle again.
I realise that as far as power throughput is
concerned, this is a dog of an idea only charging
up every other half cycle. I also don't know the
details of the trigger circuitry, it is easy
enough to detect a zero crossing but I don't know
enough to drive the tubes.
Any comments? Is an Ignitron functionally equivalent
to a SCR/Thyristor or do I have a misconception
somewhere?
Nick B.