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.
The presence of a low resistance between the terminals of the sensor causes this modulated...
The frequency of this oscillator depends on R and C (see math section for electronics). The...
This circuit was found in a 1980s documentation from the manufacturer of the integrated. The...