Prediction of drift in foil resistors

Abstract

The reliable functioning of electronic devices which incorporate high precision resistors requires maintaining the specified precision over the full life of the device. As the precision and stability of foil resistors is expressed in parts per million, a precise prediction method of resistor's behavior under different loads and time periods is required. Based on test data gathered over 4 decades of production and testing, an equation based on Arrhenius Rate Law is derived for calculation of the standard deviation of the Gaussian distribution of resistance drifts. The Mean value of the drifts' distribution is evaluated and allows the calculation of the maximum drift for any requested confidence level.