The calibration of resistors is one of the most frequently requested and the tendency is for it to increase.
The signals produced by measuring instruments are processed through resistors before display or treatment in computers. The resistors must in particular be of very high stability and generate very little noise. For telecommunications and also space, the tolerances are of the order of 1E-4 to 5.1E-5 and there temperature coefficients must be as low as 1 ppm/C or better. Aircraft computers for example must be able to operate at temperatures ranging from -50 to +40 C which would cause large resistance variations if resistors were not of very high quality.
The resistors for the intercomparison were selected in the range corresponding to the major industrial needs.
The set of four resistors intercompared consisted of: %l 1. 10 kohm resistor, manufactured by ESI, supplied by PTB.
2. 10 kohm resistor, manufactured by ESI, supplied by NPL.
3. Two distinct 1 kohm resistors manufactured by Tinsley, supplied by NPL.
The linear fit to all data shows an overall standard error of 2ppm twice the greatest uncertainty given by each participating laboratory.
Funding SchemeCSC - Cost-sharing contracts