A transformer-ratio-arm bridge for high-voltage capacitance measurements

A high-voltage capacitance ratio bridge based on the current comparator principle is described. The inherent advantages of this bridge are high sensitivity and high accuracy without the necessity of a secondary balance. By suitable design the bridge is made direct reading in capacitance ratio and dissipation factor. It has a resolution of 1 ppm (part per million) and an accuracy of approximately 10 ppm. The highest capacitance ratio internally available with full resolution is 1,000/1. Design considerations and construction details are given. Possible applications are discussed.