Tube negative ion generator (CB21002E)

This circuit was found in an old American magazine for radio amateurs. The circuit is based on a very high voltage tube of the time.

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Current or voltage differential alarm (CB20629E)
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Electronic Beep Beep (CB16469E)
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Unijunction Metronome (CB23525E)
This simple unijunction circuit is from a Radio Electronics from July 1963. It can be assembled with a...