Simple 1-tube receiver (T960E)

This 1V heater tube circuit was found on a Radio Craft from 1945. The circuit is for medium wave and can be used as a tuner.

Bistable Sonic Relay (CB18272E)
With the configuration shown in the figure, we have the relay being activated when the microphone picks...
Pulse Generator (CB18236E)
This TTL generator that can function as a control shield or external clock for microcontrollers was found in...
Absolute Value Circuit (CB19719E)
The OP07 operational amplifier is not common today, as the circuit is from an old European manual....