| 摘要 |
Method and device for capacitive determination of the position of an object. In the method use is made of two sensor plates 1, 2 located in succession in the direction of movement and coupled to a measuring circuit 8, and at a short distance from the said plates a moveable plate 3 fixed to the object, which sensor plates and moveable plate form a pair of capacitors C1, C2. The measuring circuit 8 or the moveable plate 3 are made to oscillate at a certain frequency between two voltage levels, the pair of capacitors delivering charge to the measuring circuit. In the measuring circuit the charge flow of the capacitors C1, C2 is controlled so that the charge is drawn from a predetermined voltage level Ur and is delivered to the measuring circuit in the form of mean currents I1, I2 proportional to the capacitances of the capacitors, which currents in the measuring circuit 8 generate frequencies f1, f2 proportional to the currents. The position of the object is determined by calculating the ratio between the frequencies, which is identical to the ratio of the capacitances C1, C2, following which the position of the moveable plate 3 is determined as the ratio between the difference and the sum of the capacitances of the capacitors. <IMAGE>
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