CAPACITIVE SENSOR CIRCUIT Russian patent published in 2010 - IPC G01D3/28 G01D5/24 

FIELD: physics.

SUBSTANCE: detected process parametre may be pressure, force, acceleration, inclination, temperature or some other process parametre which can be detected via a capacitive method. The device contains the following: a potential divider which includes a first and a second capacitor; a detector; a control circuit; a clock generator; a nonlinearity correction circuit; two resistors; switches. Capacitance of at least one of the capacitors varies under the effect of the process parametre. The method is characterised by that the reflected detector input signal is detected at carrier frequency and the envelope of the baseband of modulated potentials is controlled. The circuit operates on the closed loop principle, resulting in change of amplitude of modulated potentials thereby bringing the input of the detector to an average value which is close to zero.

EFFECT: high accuracy in capacitive sensors.

19 cl, 12 dwg