This alarm circuit triggers when S1 opens. The circuit from a January 1975 Radio Electronics magazine can be used with interrupt sensors connected in series.
This project was described in Radio Electronics from December 1962. The circuit is based on a...
With a touch of the sensor, the output of the 4013 changes state from high to low or vice versa. In...
Only two transistors are used in this preamp for low-sensitive transducers, such as guitar and...