This circuit automatically turns off small battery-powered devices after a certain amount of time, saving battery life. We found it in a Popular Electronics from the 90s.
Found in a 90s Elektor, this mixer makes use of integrated circuits of the time. The supply must be...
This small medium wave radio was manufactured in the 1960s in Japan. The circuit is powered by 4...
This power supply uses integrated voltage regulators for 1 A of the 78xx series. The output...