Standards for the measurement of the phase angles of resistors

A 100 ¿ phase-angle standard has been constructed by mounting a small evaporated metal-film resistor in a copper tube with side tubes for the potential connections. The inductance of this 4-terminal-pair configuration (¿6 nH) was determined by measuring the inductance of similar resistors which had been silver plated to reduce their resistance. The effective capacitance (+0.03 pF) was derived from phase-angle comparisons of 100 ¿ and 1 k¿ resistors. The uncertainty in the phase angle of the 100¿ standard is less than 0.1¿ rad for ¿ = 104, an uncertainty in time constant of less than 10ps. An a.c. bridge for the measurement of very small inductances and a 10:1 bridge for the comparison of the phase angles of resistors are described.