MIL-PRF-19978 Capacitors, Fixed, Plastic \(Or Paper-Plastic\) Dielectric \(Hermetically Sealed In Metal, Ceramic Or Glass Cases\), Established And Non-Established Reliability General Specification ForThis specification covers the general requirements for established reliability \(ER\) and non-established reliability \(non-ER\), direct current \(dc\), plastic or paper-plastic dielectric, fixed capacitors, hermetically sealed in metal or ceramic or glass cases. Capacitors meeting the established reliability requirements specified herein have failure rate \(FR\) levels ranging from 1.0 percent to 0.001 percent per 1,000 hours \(see 1.2.1.9\). These FRLs are established at a 90-percent confidence level and maintained at a 10-percent producer\'s risk and are based on life tests performed at maximum rated voltage and maximum rated temperature. An acceleration factor of 5:1 has been used to relate the life test data obtained at 140 percent of rated dc voltage at the applicable high test temperature to the rated voltage at the applicable high test temperature. This specification also covers removable mounting retainers for use with applicable capacitors \(see 3.1\). A parts per million \(ppm\) quality system is used for documenting and reporting the average outgoing quality of ER capacitors supplied to this specification. Statistical process control \(SPC\) techniques are required in the manufacturing process to minimize variation in production of ER capacitors supplied to the requirements of this specification.

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MIL-PRF-19978K

6.6 Failure rate L. Failure rate L has been canceled from this specification.

6.7 Tin whisker growth (see 3.5.3.5). The use of alloys with tin content greater than 97 percent, by mass, may

exhibit tin whisker growth problems after manufacture. Tin whiskers may occur anytime from a day to years after

manufacture and can develop under typical operating conditions, on products that use such materials. Conformal

coatings applied over top of a whisker-prone surface will not prevent the formation of tin whiskers. Alloys of 3

percent lead, by mass, have shown to inhibit the growth of tin whiskers. For additional information on this matter,

refer to ASTM-B545 (Standard Specification for Electrodeposited Coatings of Tin).

6.8 PIN. This specification requires a PIN that describes codification and classification and appropriate

references to associated documents (see 1.2 and 3.1).

6.9 Environmentally preferable material. Environmentally preferable materials should be used to the maximum

extent possible to meet the requirements of this specification. As of the dating of this document, the U.S.

Environmental Protection Agency (EPA) is focusing efforts on reducing 31 priority chemicals. The list of chemicals

and additional information is available on their website at https://www.epa.gov/osw/hazard/wastemin/priority.htm.

Included in the EPA list of 31 priority chemicals are cadmium, lead, and mercury. Use of these materials should be

minimized or eliminated unless needed to meet the requirements specified herein (see Section 3).

6.10 Subject term (key word) listing.

Part Per Million (ppm)

Statistical process control (SPC)

6.11 Changes from previous issue. The margins of this specification are marked with vertical lines to indicate

where changes from the previous issue were made. This was done as a convenience only and the Government

assumes no liability whatsoever for any inaccuracies in these notations. Bidders and contractors are cautioned to

evaluate the requirements of this document based on the entire content irrespective of the marginal notations and

relationship to the last previous issue.