This receiver was found in a 1924 book by Gernsback. The circuit uses three tubes and is powered by 3 batteries of different voltages, common at the time.
This 8-channel converter was found in a 1970s American documentation. The integrated circuits used are...
This circuit is from a 1995 documentation. Several CMOS integrated circuits are used to produce...
Found in Radio Electronics, this circuit is intended to activate the lighting system of garages...