This circuit is from a 1967 documentation. It consists of a sensor for memories used at the time. It can be made with modern equivalent transistors. Note the 4 V symmetrical power source.
This circuit recognizes a tone determined by the tuned input circuit (R3 / R4 / C2). The circuit...
This CMNOS crystal-based circuit generates a 2 Hz signal. It was found in the October 1994 issue of...
This is one of the possible configurations using the LM139, 239 or 339 voltage comparators. The...