| 摘要 |
The capacitive measurement-value pick-up contains a first and a second measurement integrator (1, 2) which in each case comprise an operational amplifier (4, 5) with ohmic input resistor (6, 7) with feedback via a measuring capacitor (10, 11) with measurement-value-dependent capacitance. The first measurement integrator (1) is connected to the positive input and the second measurement integrator (2) is connected to the negative input of a subtracting element. To create a capacitive measurement-value pick-up which generates an error-free alternating signal independent of interference and which can be transmitted without error over relatively long signal lines, a reference integrator (3), which consists of an operational amplifier (6) with ohmic input resistor (9) and a capacitor (12) with measurement-value-independent capacitance in the feedback circuit is connected in parallel with the measurement integrators (1, 2). The output of the reference integrator (3) is connected to the positive input of the subtracting element (13) which, in turn, is connected via a Schmitt trigger (14) to the inputs of the measurement integrators (1, 2) and of the reference integrator (3). <IMAGE>
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