MIL-PRF-39005 Resistors, Fixed, Wirewound \(Accurate\), Nonestablished Reliability, Established Reliability, General Specification ForThis specification covers the general requirements for nonestablished reliability \(non-ER\), established reliability \(ER\), accurate, wire-wound, fixed resistors that have a maximum resistance tolerance of 1 percent and a high degree of stability with respect to time under specified environmental conditions. The resistors are capable for continuous full-load \(or voltage\) operation at any ambient temperature up to 125??C, and when derated, up to 145??C \(see 6.5\). They are not capable for application where the alternating current \(ac\) characteristics are of critical importance. ER resistors have life failure rates \(FR\) ranging from 1.0 percent to 0.001 percent per 1,000 hours \(see 1.2.1.5\). These FR are established at 60-percent confidence level on the basis of the life tests. The FR, identified by the appropriate symbol, is referred to operation at full rated voltage and temperature.

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MIL-PRF-39005G

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. This section is not applicable to this appendix.

A.3. SUBMISSION

A.3.1 Product levels. Qualification of the C (non-ER) level is predicated upon meeting the ER

qualification requirements for FRL P (see A.4.2). The procedure for submitting samples to become

qualified to the initial FRL M is specified in A.3.2.

A.3.2 Sample. When qualification is sought for a resistance range, a sample consisting of 343 sample

units in the same style, tolerance, and terminal type shall be submitted together with 2 unenclosed

sample units of the same style for group IA of table IX and a statement indicating the lowest resistance

value manufactured. The number of sample units in group II and group VIII inclusive, of table IX, and the

applicable resistance value, shall be as specified in table A-I. A minimum of 10 additional sample units

shall be submitted for group IB tests. When terminal type "L" in a style is submitted, qualification for

terminal type "U" shall be granted with the submission of 60 additional types "U" to group I, group IA,

group III, and group V of table IX. Samples shall be divided as indicated by table IX for the applicable test

group. When terminal type "U" in a style is submitted, qualification for type "L" shall be granted with

submission of 70 additional type "L" samples to group I, group IA, group IB, group III, and group V of table

IX. Samples shall be divided as indicated by table IX for the applicable test group.

A.3.3 Description of items. The manufacturer shall submit a detailed description of the resistors being

submitted for inspection, including material used for the protective coating or enclosure and the type of

wire used in the resistance element. After qualification has been granted, no changes shall be made in

materials, design, or construction without prior notification to the qualifying activity.

A.4. EXTENSION OF QUALIFICATION

A.4.1 Extent of qualification by tolerance. The resistance range included in the qualification of any one

resistor style shall be between the highest resistance value tested and 0.1 ohm, provided the same

materials are used within the range qualified. Qualification of resistors by initial resistance tolerance shall

qualify resistors of the same style and resistance range in any of the other initial resistance tolerances as

listed in table A-II, provided the same coating, enclosure, and materials are used.