Spannungs-Frequenz-Wandler und Widerstands-Frequenz-Wandler

A voltage frequency converter and a resistance frequency converter comprise an integrator circuit including a downstream comparator circuit and a feedback circuit between the output of the comparator circuit and the input of the integrator circuit. The coverter accuracy is enhanced according to the invention by the feedback branch being provided with a pulse generating circuit controlled by an oscillating crystal, said pulse generating a circuit responding at an edge of the output signal and generating a pulse having a period defined by an oscillating crystal, whereas the input of the converter circuit is connected to a voltage to be measured by a first resistor and to a reference voltage source by a resistance to be measured and, on the other hand, is connected to the reference voltage source or to a voltage derived therefrom by a series circuit of a further resistor and of a switch controlled by the pulse generating circuit