Abstract: The electronic monitoring circuit for monitoring one of a group of series-connected capacitor units in an intermediate circuit in order to detect short-circuiting of one of the capacitor units includes a device for deriving a reference voltage (14) from an intermediate-circuit voltage (L(+), L(?)) applied across the series-connected capacitor units (1, 2), a device for generating a control signal consisting of a voltage difference between the reference voltage (14) and a junction voltage at a junction (13) between two capacitor unit (1, 2) and a device for generating an error signal when said voltage difference falls below or exceeds an activation threshold voltage thus indicating that one of the capacitor units (1,2) has been short-circuited. The activation threshold voltage corresponds to a breakdown voltage of a zener diode provided in the monitoring circuit.

Abstract: The electronic monitoring circuit for monitoring one of a group of series-connected capacitor units in an intermediate circuit in order to detect short-circuiting of one of the capacitor units includes a device for deriving a reference voltage (14) from an intermediate-circuit voltage (L(+), L(?)) applied across the series-connected capacitor units (1, 2), a device for generating a control signal consisting of a voltage difference between the reference voltage (14) and a junction voltage at a junction (13) between two capacitor units (1, 2) and a device for generating an error signal when said voltage difference falls below or exceeds an activation threshold voltage thus indicating that one of the capacitor units (1,2) has been short-circuited. The activation threshold voltage corresponds to a breakdown voltage of a zener diode provided in the monitoring circuit.