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.
This sensitive two-transistor circuit was found in the June 1965 Radio Electronics magazine. The...
This circuit, obtained in an old publication, causes a second telephone bell to be played in a...
Found in a1969’s neon lamp documentation, this circuit uses a high voltage transistor. The output...