This commercial receiver for the mid-wave range of the 1960s was found in Japanese documentation at the time. The supply is 9 V, and the configuration is superheterodyne type.
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...