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Old 08-14-2012, 11:58 PM
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citfta citfta is online now
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Hi Graham,

Thanks for the very interesting links. I just finished reading the rest of the Perreault paper. I have to say all of what he says does make sense. I know that the tungsten welding electrodes are supposed to be thoriated. I wonder if we could use them to make our own ion generator? Some time ago I read that someone thought the E. V. Gray circuit would work like it was supposed to have worked if it had a tungsten welding rod in the tube.

Quote:
Originally Posted by GSM View Post

The secret within those early thermionic tubes were filaments of thoriated tungsten used by manufacturers competing for efficiency per directly heated filament Watt.

A thoriated tungsten cathode can be induced to release additional electrons if it is bombarded with a lesser electron stream attracted from an anode via a positive grid potential. If the tube is oscillated, then those additional cathode released electrons may be conducted away, again via the grid w.r.t. the anode.

Do please take a look at the TH Moray tube circuits,
also page 37 here >
http://elearning.zaou.ac.zm:8060/Sci...0Perreault.pdf

http://www.tubebooks.org/tubedata/taylor_tubes.pdf

There was a very recent video of someone doing this on YT, but I did not retain a link, and modern indirectly heated cathode tubes, even thoria coated types, would likely succumb to ion poisoning in a way which early thoriated wire heated types were not susceptible.

Cheers ............ Graham.
Later,
Carroll
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