This circuit was found in the July 1978 issue of Radio Electronics magazine. The circuit uses a common digital voltmeter as the indicator. The sensors are integrated circuits of the time.
Suggested by an American documentation for 1969 neon lamps, this circuit provides SCR control with...
This circuit is designed to measure very weak currents, in the order of picoamperes. We found it...
The 709 integrated circuit is not common today. The circuit is from American technical...