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

TABLE IX. Qualification inspection - Continued.

1/ Failure of a resistor in one or more tests of a group shall be charged as a single defective.

2/ The manufacturer shall verify by certification that these requirements have been met in fabricating

resistors furnished to this specification.

3/ Nondestructive tests.

4/ Test shall not be performed if manufacturer presents certified data proving test has been

performed on the qualification sample.

5/ Marking shall be considered defective if marking is illegible or incorrect.

6/ This test shall be performed not less than 10 minutes nor more than 30 minutes after the

preceding test.

7/ Test shall not be performed if manufacturer certifies that all external materials are fungus

resistant.

When group C requirements were not met and the manufacturer has taken corrective action satisfactory

to the Government, group C retesting shall be instituted. A summary of the retesting shall be forwarded

to the qualifying activity within 30 days after completion of the retest. All reports are to be certified by a

responsible company official and Government inspector.

If group C test requires a comparison of "post-test" reading with initial readings (delta measurements), the

verification of qualification summary shall include the maximum and minimum delta changes for each

inspection lot. For life test, delta R readings shall be reported at each interval in which reading is taken.

4.6 Conformance inspection.

4.6.1 Inspection of product for delivery.

4.6.1.1 Non-ER resistors. Inspection of product for delivery shall consist of the requirements in 4.6.3.1.

4.6.1.2 ER resistors. Inspection of product for delivery shall consist of group A and group B

inspections. Group B inspection for preparation of delivery is not required when the qualifying activity has

allowed group B testing to be performed annually (see table XIII).

4.6.2 Inspection and production lot.

4.6.2.1 Inspection lot. The total number of pieces in any given lot submitted for conformance

inspection shall not exceed the number of pieces accumulated from 1-month production. Provided the

same materials, methods, and production lines are used, the manufacturer may combine styles,

resistance values, and resistance tolerances for lot formation. However, test data on each style shall be

kept separate.

4.6.2.2 Production lot (ER only). A production lot shall consist of all resistors of the same style,

nominal resistance value, resistance tolerance and terminal type. Manufacture of all parts in the lot shall

have been started, processed, assembled, and tested as a group. Lot identity shall be maintained

throughout the manufacturing cycle. Non-ER and ER lots shall be kept separate.