Found in a 1969 neon lamp publication, this circuit provides two voltages under very-low currents. Neon lamps are types of the time.
Other CMOS gates can be used in this sensor, which we found in the July 1995 Electronic Now...
This circuit is from the American magazine that no longer exists Science & Electronics,...
Using the 4046 PLL we found this circuit in the December 1989 Radio Electronics. The circuit...