AC millivoltmeter (CB21862E)

This circuit is from a 1974 Ferranti transistor manual. The circuit is analog, and the components used are period types.

Schmitt trigger (CB7983E)
This simple trigger circuit was found in a 90’s American documentation. The integrated circuit is...
Power Outage Alarm (CB24152E)
This sensitive circuit was found in the August 1971 issue of Radio Electronics magazine. The SCR...
Varicap Beat Oscillator (CB25649E)
The varactor or varicap diode tunes the signal for listening to SSB signals on a common receiver. The...