This capacitive sensor that operates with a high frequency oscillator was found in Radio Electronics from the 90's. The circuit operates around 300 kHz.
We found this circuit in an old Mullard (Philips) documentation on the 555 and 556 integrated circuit...
This circuit was obtained from an Electronic Design of 1968. The circuit uses components of the...
This circuit was found in a 70s National Semiconductor manual. It has a different output way for...