Abstract: An analog-digital converter in which a capacitor is charged or discharged by a reference current with the aid of transistor switches, a continuous current flows through the capacitor which is determined by an input difference voltage. One side of the capacitor is connected via a comparator to a flip-flop, to which flip-flop a clock signal is applied and which flip-flop drives the transistor switches. The other side of the capacitor is connected to the first input of a differential amplifier, which differential amplifier forms part of a negative feedback loop which maintains the voltage at the first input of the differential amplifier equal to the voltage which is applied to the second input of the differential amplifier.

Abstract: A measuring arrangement for measuring the effective value of an a.c. signal. Said a.c. signal is applied to a first thermal convertor, while a d.c. output signal is applied to a second thermal convertor. The two thermal convertors differentially drive a differential amplifier, which at its outputs delivers the d.c. output signal. For values of the d.c. output signal which are smaller than a threshold value, a negative feedback signal which linearly depends on said d.c. output signal is applied via an additional negative-feedback network to at least one of the inputs of the differential amplifier. This facilitates zero-point adjustment, and also allows the measuring speed to be increased.