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.
This circuit was obtained from a 1967 General Electric manual. The circuit uses components of the time,...
This circuit uses an amplifier from National Semiconductor, uncommon nowadays. The numbers in...
This circuit is powered by the source of the equipment under analyze. We found this configuration in a 1974...