Capacitive measuring device

Abstract

A capacitive measuring device with a measuring electrode (3) arranged some distance from a counter-electrode (8), a dielectric material for analysis is arranged between the electrodes (3, 8), and a measuring current (IC) is supplied to the measuring electrode (3) and the capacitance-dependent capacitor voltage (UC) is measured and evaluated. The measuring electrode (3) is surrounded by a plurality of guard ring and/or auxiliary electrodes (13, 6N, 6NA) spaced apart therefrom in a staggered arrangement and at least partly covering the side walls (18), and each of which is constantly being corrected via a potential-controlling circuit (17) to the potential of the measuring electrode (3), so as to thereby largely eliminates leakage currents to the guard electrodes (13, 6N, 6NA), in the region of the measurement zone the side wall (18) being virtually completely covered with additional guard electrodes (61-6N; 61A-6NA), divided in a ribbon shape parallel to the measuring electrode (3) or divided in a two-dimensional grid, and each of the guard electrodes is wired to its potential-controlling circuit (17) in a manner that minimizes any flow of current into the guard electrodes (61-6N; 61A-6NA).

Dependencies are inferred from the claim text.