This circuit was obtained from the PE Hobbyist Electronics publication of 1980. The circuit is based on the 555 and is simple to assemble and can be used to control the brake lights.
This circuit was found in a Popular Electronics from the 90's. The output signal can be applied to a...
A small loudspeaker (2.5 or 5 cm) can be used as a low impedance microphone. A preamplifier and...
This flip-flop circuit with general purpose transistors was found in American documentation from...