CIRCUIT ARRANGEMENT FOR AUTOMATIC CONTROL OF THE VOLTAGE OF AN ELECTRICAL FILTER

摘要

A control unit comprises a charging circuit which connects a guide capacitor to a source of DC voltage whereby a control voltage supplied to a control system is produced by the control unit in accordance with the voltage of a guide capacitor. A discharging circuit is connected in parallel with the guide capacitor and includes a controllable resistor having a resistance value dependent upon the voltage of the filter. A photoelement is in operative proximity with a glow lamp in a manner whereby light produced by the glow lamp impinges on the photoelement. The photoelement is coupled by a circuit to the discharging circuit for supplying a control signal dependent upon the irradiation of the photoelement whereby the control signal controls the controllable resistor of the discharging circuit to a low resistance value when the glow lamp does not glow and controls the controllable resistor to a high resistance value when the glow lamp glows. A cutoff circuit supplies a cutoff signal to the control system and the control system controls a control circuit to interrupt the filter current without delay when a sparkover occurs in the filter.