This circuit is from a 1968 documentation using one of the first integrated circuits available at the time, the TAA370. The circuit is powered by 1.3 V using a 200 ohm handset.
This blocking oscillator configuration was found in a 1964 American book. The circuit can be...
This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is...
This transmitter, indicated for espionage applications, is permanently powered by the power grid....