This circuit was found in a Popular Electronics of the 1990s. The sensor is a rotating mechanical system with a propeller-driven magnet to count pulses with a reedswitch.
This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is based...
The number of pulses produced by this circuit depends on the switch pressed. The circuit is from...
This ultra-low power metronome was found in a 1991 documentation. The output transistor is general...