A new ultralow-frequency bridge for dielectric measurements

A new bridge, operating in the frequency range 0.001–10,000 Hz, and featuring improved convenience of operation and high accuracy, has been built at the National Bureau of Standards, under NASA sponsorship. Though designed chiefly to measure dielectric properties, it is also capable of measuring the conductance of resistors in the range 10
⁸
–10
¹⁴
Ω. Large loss angles are no great problem. In the frequency range 0.01–15 Hz, capacitance resolution of 5 ppm and loss-angle resolution of 5 μrad is easily achieved. It is not yet known what resolution and accuracy will characterize the frequencies between 70 and 10, 000 Hz, but it is expected to diminish. Existing bridges cover this range better.