| 摘要 |
A circuit arrangement determines the closing instant of a valve with a coil that actuates an armature. The circuit has a voltage divider with at least three resistors connected to a measuring node of the coil and to ground. The first resistor is highly resistant in comparison with the other resistors of the voltage divider. A differential amplifier has its output connected to its inverting input via a fourth resistor and its non-inverting input receives a voltage from the voltage divider that represents the current in the coil. A parallel circuit of a capacitor and a resistor is connected between the inverting input and ground. A controllable switching element has a controlled path between the first resistor and the parallel circuit, and a control connection connected to the positive supply potential of the differential amplifier.
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