Normalised capacitance measuring device - has stable oscillator feeding up=down counter circuit including memory system

摘要

A capacitance measurement circuit operates cyclically with a measuring phase and a normalising phase. It includes a high stability oscillator to which the unknown capacitor and a normalisation capacitor are connected. The evaluating circuit includes an up-and-down counter which triggers a second counter when a null state is reached. Coupled to the second counter is a memory, counter and indicator circuit which displays the normalised value of the unknown capacitance. A control circuit is coupled to the two counters. A clock pulse generator may supply different clock frequencies in the up and down counting modes.