Filament source (T398E)

Despite being transistorized, this is a constant current source circuit for 1 V valve filaments such as the 1H4 tube.

Multiplexed AD Converter (CB9023E)
This 8-channel converter was found in a 1970s American documentation. The integrated circuits used are...
Sound Effects Generator (CB17012E)
This circuit is from a 1995 documentation. Several CMOS integrated circuits are used to produce...
Automatic lamp control (CB6847E)
Found in Radio Electronics, this circuit is intended to activate the lighting system of garages...