Circuit system for the generation of a direct control voltage depending upon an alternating voltage

Claim 1

A circuit system for generating a direct control voltage dependent upon an alternating voltage, comprising: a charging capacitor across which the direct control voltage appears; a first circuit connected for subjecting said capacitor to a charge change in a first direction at a rate which is a function of the amplitude of the alternating voltage; a second circuit connected for subjecting said capacitor to a charge change in a second direction opposite to the first direction and having a variable conductance which determines the rate at which it effects such charge change, and control means including a time-lag element connected to said second circuit and responsive to a sudden increase in the alternating voltage for reducing the conductance of said second circuit and to a decrease in the alternating voltage below a selected threshold value for increasing the conductance of said second circuit; wherein said second circuit includes means defining a buffer circuit operative for causing the rate of charge change effected by said second circuit after such sudden alternating voltage increase to vary as a function of the duration of the time interval between such sudden increase and a succeeding decrease in the alternating voltage below the selected threshold.