Resistors C5–60 in Metrological Practice: Operational Experience

The search for new types of resistors that could potentially be used for long–term storage of electrical resistance values with the highest attainable accuracy has always been an urgent task of metrology. In this paper, we have studied the problem of choosing a resistor for transmitting and storing a unit of electrical resistance when creating an Ω standard based on the quantum Hall effect in the time interval between reproductions of a unit. The choice of C5–60 resistors, which were not originally intended for use as standards of higher levels of the electrical resistance verification circuit, is substantiated. In 1990–2022 detailed experimental studies, including studies of long–term stability, of C5–60 type resistors have been carried out. Some of the investigated resistors are included in the State secondary standard of electrical resistance unit in the range of values from 0.1 Ω to 13 kΩ based on the quantum Hall effect. Comparisons of the investigated resistors with resistance measures traditionally used to create standards for the unit of electrical resistance are carried out. It has been established that C5–60 resistors have a low temperature coefficient of resistance, they are easy to stabilize using a thermostat without a temperature–controlled oil bath. The long–term stability of the C5–60 resistors turned out to be uniquely high and allows these resistors to be used as discharge standards for storing a unit of electrical resistance.