Designed for the audio track, this circuit was found in a Popular Electronics from the 90's. Other operational can be used and R7 can be 470 k. The frequency is 1 kHz.
This simple CMOS metronome circuit can be mounted in a small box, providing both sound and light...
Although indicated in the original publication of the 1980s as a capacitance switch, the circuit...
In the figure below we have a simple way to do chroming, silvering or another type of...