Simple 5V regulator (CB8815E)

This simple 5.6 V regulator circuit was found in a 1966’s Philips. The zener can be changed to obtain other voltages.

Decade Counter with Nixie Tube (CB20141E)
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
Crystal Radio (CB14015E)
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
Headphone amplifier (CB23888E)
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...