This circuit was found in an American documentation from the 1980s. The sensitivity ranges from 100 mV to 1 V. The supply must be done with an excellent filtering source.
We found this circuit in Radio Electronics Special Projects from 1992. The circuit turns on the...
We found this circuit in the Texas Instruments' Linear Circuits Applications. It uses an...
This capacitive sensor that operates with a high frequency oscillator was found in Radio...