Aspects Affecting the Reliability of a Carbon Composition Resistor

The mechanism of resistance drift of a 1-watt carbon composition resistor has been investigated, based on a study of the internal construction. Predominant physical and chemical processes under given environments are postulated. Aging mechanisms, the behavior of resistance drift under various environmental conditions over a period of time and failure modes are considered. Restrictions on application of the part and criteria for part selection are established. Failure analyses have also been performed to verify the postulated behavior mechanisms.