Patent ID: 7652487

Claim:
Circuit arrangement for detecting the capacitance or change of capacitance of a capacitive circuit element or a component, comprising: a control unit, a monostable multivibrator triggered by the control unit, a constant current generator and an evaluation unit, wherein the monostable multivibrator has a first input which is connected to the control unit, a second input which is connected to the capacitive circuit element or component, and an output, wherein an output signal or output signals is produced at the output of the monostable multivibrator in response to the monostable multivibrator being triggered by the control unit, wherein said output signal or output signals have a time duration which is proportional to the capacitance of the capacitive circuit element or component, wherein an integrator means is connected to the constant current generator for converting the current delivered from the constant current generator into a signal voltage proportional to said time duration, wherein the output of the monostable multivibrator is connected upstream of the constant current generator and wherein the constant current generator is controllable by the output signal or output signals of the monostable multivibrator, and wherein the evaluation unit is adapted to produce a detection value corresponding to the capacitance or change of capacitance of the capacitive circuit element or component from the signal voltage.