This circuit was obtained from an Electronics Design of 1964. The circuit makes use of tunnel diodes that are uncommon today. The circuit works with very weak signals.
This wired intercom circuit was found in an English publication from the 80's. The integrated...
This 741 operational circuit can be found with slight variations in this section and on this site....
In the circuit of the figure, we have an application different from 4093. The astable...