This circuit was found in a 1968 EEE. The circuit makes use of logic gates of the time and can be tested with equivalents from modern families.
This sensor was published in Radio Electronics magazine in April 1962. The two-transistor circuit...
Another of the many similar configurations we have in this section. This one is from a Radio...
This circuit like the previous one is intended for 24V x 3W solenoids being connected from the...