We found this circuit in a 1980s General Electric documentation. It appears from other sources in this section. The circuit makes use of diacs and SCRs of the time.
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,...