Correlation Between Thick-Film Resistance Values

Experiments have been performed with thick-film resistor arrays which provide information about ,the correlation between the values of untrimmed thick-film resistors. The results confirm that such a correlation does exist and is approximately inversely proportional to the distance separating two resistors. The results also show that the resistor area has a small effect on the correlation and that the resistor aspect ratio has very little effect. The results indicate that the correlation coefficient between thick-film resistors is always positive. The most important result is that there is a significant amount of correlation between two resistors on a substrate that are made of different pastes. This last correlation is caused by the common conductor printing step.