| 摘要 |
A method for operating a capacitance measuring instrument exhibiting measurement input terminals (A, B), which is used for measuring the capacitance (C1, C2) of an object to be measured (a, b), having - a capacitance measuring unit (CM), for example capacitance measuring bridge and its output amplifier, and - an overload protection unit (R1) for protecting the capacitance measuring unit (CM) against a dangerously high external voltage (UAC, UDC) at the measurement input terminals (A, B), in which arrangement - when the measurement input terminals (A, B) are applied to the object to be measured (a, b), first only the overload protection device (R1) but not the capacitance measuring unit (CM) is connected to the object to be measured (a, b) via the measurement input terminals (A, B), - then the initial currents or voltages at the measurement input terminals (A, B) are measured by means of the overload protection unit (R1) equipped with a measuring arrangement (A/D, PR), whereafter --- the capacitance measuring unit (CM) is not connected to the measurement input terminals (A, B) if the initial currents indicate external voltages (UAC, UDC) which are dangerously high for the capacitance measuring unit (CM), and --- the capacitance measuring unit (CM) is connected to the measurement input terminals (A, B) if the initial currents indicate external voltages (UAC, UDC) which are not dangerously high. <IMAGE>
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