RELIABLE LONG LIFE COMPONENT STUDY XLT METAL FILM RESISTOR.

The performance of the XLT under the conditions of the test matrix justify the rating of this resistor as a 14 watt resistor. The estimated failure rate for 14 watt operation at 125C and 85C are 0.0008 and 0.0003 percent per thousand hours, respectively, when a failure is defined as a delta R exceeding 2.0 percent. Independent data exists that indicates a selection is possible between high and low performance units at the 14 watt level and it is possible to discriminate between the two. The requirement of MIL-R-55182 that the life test sample be evaluated against a limit of 0.25 is prohibitive with respect to XLTs designation as a 14 watt resistor and must be modified if the resistor is to be so rated. The temperature coefficient characteristic is constant and does not change within the limits of experience on this matrix test. The XLT is capable of meeting an extended moisture resistance test of 30 cycles.