Found in a 90s documentation, this circuit appears in other configurations on this site. The circuit can be powered with voltages from 5 to 12 V.
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,...