Two sensors are used in this simple remote-control circuit, one to switch on and one to switch off the relay. The circuit is from 1986 documentation. The transformer has 12 V of secondary.
This polarity inverter circuit for voltages down to about -12 V was found in the December 1992...
This circuit is old, from an English publication from 1979, so the indicated sensor is no longer...
This stage of two complementary transistors was found in a 1977 Radio Handbook. Transistors admit current...