The 2972A Series of standard resistors are metal foil resistors, while the previous 2972 Series were winding resistors.
The error range of the 2972A Series is much smaller than those of the previous 2972 Series, as demonstrated by the resistance temperature coefficient curves.
Precision temperature control equipment such as oil baths, are not needed for measurement and calibration. The 2972A can do these in an air environment.
Features
Traced to the National Standard for high accuracy; test (calibrated) accuracy of ±5 ppm
Resistance temperature coefficient. Excellent temperature characteristics in the range of 0° to 50° C (32° to 122° F) resistance temperature coefficient less than ±2.5 ppm / ° C
A variety of models. Eight models with nominal resistance values ranging between 0.001 Ohm and 10 KiloOhms
Precision temperature control equipment, such as an oil bath, not needed for calibration due to marked improvement in resistance temperature coefficient