This radio for the AM band has the traditional superheterodyne configuration with several transistors and integrated audio amplifier circuit. The circuit is from the 70s.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...