MIL-PRF-39009 Resistors, Fixed, Wire-Wound \(Power Type, Chassis Mounted\), Nonestablished Reliability, Established Reliability, General SpecificationThis specification covers the general requirements for nonestablished reliability \(non-ER\), and established reliability \(ER\), power type, wire wound, fixed resistors which utilize the principal of heat dissipation through a metal mounting surface. These resistors have initial resistance tolerances of ??1 percent. These resistors are suitable for continuous full load operation at an ambient temperature of +25 degrees C, and when derated up to +250 degrees C \(see figure 1\). These resistors should not be used in circuits where their ac performance is of critical importance in the operation of such circuits. However, provisions have been made in particular styles to minimize inductances \(see 3.1\). These resistors will have life failure rate levels \(FRL\) ranging from 1.0 percent to 0.001 percent per 1,000 hours \(see 1.2.1.4\). These FRL are established at a 60 percent confidence on the basis of the life tests. The FRL, identified by the appropriate symbol, is referred to operation at full rated wattage at +25 degrees C, with a permissible change in resistance of ??2 percent as the criteria for failure.

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MIL-PRF-39009E

APPENDIX A

PROCEDURE FOR QUALIFICATION INSPECTION

A.1 SCOPE

A.1.1 Scope. This appendix details the procedure for submission of samples, for qualification

inspection, of resistors covered by this specification. The procedure for extending qualification of the

required sample to other resistors covered by this specification is also outlined herein. This appendix is a

mandatory part of the specification. The information contained herein is intended for compliance.

A.2 APPLICABLE DOCUMENTS

A.2.1 General. The documents listed in this appendix are specified in sections A.3, A.4, and A.5 of this

specification. This section does not include documents cited in other sections of this specification or

recommended for additional information or as examples. While every effort has been made to ensure the

completeness of this list, document users are cautioned that they must meet all specified requirements

documents cited in sections A.3, A.4, and A.5 of this specification, whether or not they are listed.

A.2.2 Government documents.

A.2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and

handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the

issues of these documents are those cited in the solicitation or contract.

DEPARTMENT OF DEFENSE STANDARDS

Leads for Electronic Components Parts.

(Copies of these documents are available online at https://assist.daps.dla.mil/quicksearch/ or

https://assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue,

Building 4D, Philadelphia PA 19111-5094.)

A.2.3 Order of precedence. In the event of a conflict between the text of this document, and the

references cited herein (except for related specification sheets) the text of this document takes

precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a

specific exemption has been obtained.

A.3 SUBMISSION

A.3.1 Product levels. Qualification of the C (nonestablished reliability) level, is predicated upon meeting

the established reliability qualification requirements for FR level P (see A.4.1). The procedure for

submitting samples to become qualified to the initial failure level M is specified in A.3.2.

A.3.2 Sample. A sample consisting of 252 units in each style shall be subjected to the qualification

inspection specified in table V, in the order shown. All sample units shall be subjected to the inspection of

group I and group IA. The sample units shall then be divided as specified in table V for group II to group

V. In addition, ten sample units shall be subjected to group VI.