This circuit was found in an American publication from 1965. The circuit uses components from that time. No information was given about the excitation transformer. Observe the high input power.
This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is...
This 3-decade operating range VCO was found in a 90s Popular Electronics. The circuit uses...
This circuit was found in an Electronic Design from the 90s. Operational amplifiers admit modern...