This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V power source must be isolated from the mains.
We found this circuit in the December 1998 issue of Electronics Now magazine. RF transistors such...
This circuit was found in an American documentation from the 80's. The sensor is a special...
This circuit automatically controls the degree of illumination. As the circuit is from 2001, it...