This circuit was found in the July 1986 issue of Radio Electronics magazine. The circuit has a loudspeaker warning system. The sensor is the ceramic capacitor C1 which acts as a transmission line.
This general-purpose transistor amplifier stage was found in the November 1993 issue of...
The integrated circuits suggested in this project are double equivalents of the well-known 555....
This shield can be controlled by positive or negative voltages of the sensor acting as a...