Abstract: A method actuates a fuel injector having a coil drive with a solenoid and a magnet armature. The magnet armature can be moved along a longitudinal axis by a magnetic field generated by the solenoid. In the method, an amplification voltage is applied to the solenoid at a predefined point in time to move the magnet armature from a closed position into an open position. The amplification voltage is made available by a voltage-regulated direct voltage transformer from a supply voltage. The direct voltage transformer has a storage capacitor for supporting the voltage made available at the output of the direct voltage transformer. The storage capacitor is charged to a pilot control voltage by the amplification voltage before the given point in time, with the result that the voltage present at the solenoid is higher than the amplification voltage at the predefined point in time.

Abstract: A device for measuring the value of a resistor has a first RC element with a first time constant and a second RC element with a second time constant. The first RC element has a first capacitor and a resistor. The second RC element has a second capacitor and the resistor to be measured. An evaluation circuit charges the first and second capacitors to a first and a second voltage, respectively, and initiates their discharge. The evaluation circuit measures the time that elapses from the start of the discharge to the instant at which the voltages across the capacitors are equal, and determines the value of the resistor from the values. In the event that the first time constant is larger than the second time constant, the first voltage is smaller than the second voltage, and vice versa.

Abstract: A method actuates a fuel injector having a coil drive with a solenoid and a magnet armature. The magnet armature can be moved along a longitudinal axis by a magnetic field generated by the solenoid. In the method, an amplification voltage is applied to the solenoid at a predefined point in time to move the magnet armature from a closed position into an open position. The amplification voltage is made available by a voltage-regulated direct voltage transformer from a supply voltage. The direct voltage transformer has a storage capacitor for supporting the voltage made available at the output of the direct voltage transformer. The storage capacitor is charged to a pilot control voltage by the amplification voltage before the given point in time, with the result that the voltage present at the solenoid is higher than the amplification voltage at the predefined point in time.

Abstract: A device for measuring the value of a resistor has a first RC element with a first time constant and a second RC element with a second time constant. The first RC element has a first capacitor and a resistor. The second RC element has a second capacitor and the resistor to be measured. An evaluation circuit charges the first and second capacitors to a first and a second voltage, respectively, and initiates their discharge. The evaluation circuit measures the time that elapses from the start of the discharge to the instant at which the voltages across the capacitors are equal, and determines the value of the resistor from the values. In the event that the first time constant is larger than the second time constant, the first voltage is smaller than the second voltage, and vice versa.