This circuit has 4 operating modes and was found in the 1995 Encyclopedia of Electronic Circuits Volume 5. The circuit works with light or heat sensors.
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...