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Abstract

An apparatus and method for measuring the ratio of the capacitance values C.sub.1, C.sub.2 of two capacitors having very small capacitances, where the capacitors to be compared are interconnected by means of one of their one electrodes. A signal voltage U.sub.i (t) which can be differentiated, can be reproduced over at least two signal periods and has defined slopes is applied to the interconnected electrodes of the capacitors. The two other electrodes of the capacitors are each connected to current amplifiers (3,4). The amplified output signals U.sub.1 (t), U.sub.2 (t) of the two capacitors are supplied to an A/D convertor and during a first signal period, two digital amplitude values Us.sub.1, Us.sub.2 of the output signals of the one capacitor at an interval of half a signal period (T/2) are determined and, subsequently thereto and likewise at an interval of half a signal period, during the second signal period, two digital amplitude values Us.sub.3, Us.sub.4 of the output signals of the other capacitor are determined. These values are utilized to determine and output the capacitance ratio in accordance with ##EQU1## The circuit arrangement can advantageously be used in an apparatus for inclination and/or acceleration measurements, whose sensor comprises two fixed electrode plates (10, 11) and a capacitor plate (15) arranged in a moving manner between them.

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