The diodes are for general use and the transistors also in this Exclusive-OR circuit. The circuit may have the values of the resistors changed to 5 V logic.
This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V...
This commercial medium and short-wave radio was manufactured in Japan in the 60s. The circuit has...
General Electric suggests this circuit in an 80's documentation. The circuit makes use of PUTs...