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

2.3 Non-Government publications. The following documents 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.

ELECTRONIC INDUSTRIES ASSOCIATION (EIA)

Assessment of Outgoing Nonconforming Levels in Parts Per Million (ppm).

Statistical Process Control Systems.

(Application for copies should be addressed to Electronic Industries Association (EI, 2500 Wilson

Boulevard, Arlington, VA 22201-3834.)

2.4 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.

3. REQUIREMENTS.

3.1 Specification sheets. The individual item requirements shall be as specified herein and in

accordance with the applicable specification sheet. In the event of any conflict between the requirements

of this specification and the specification sheet, the latter shall govern.

3.2 Qualification. Resistors furnished under this specification shall be products that are authorized by

the qualifying activity for listing on the applicable Qualified Products List (QPL), before contract award (see

3.3 QPL system. The manufacturer shall establish and maintain a QPL system for parts covered by

this specification. Requirements for this system are specified in MIL-STD-790 (all product levels) and

MIL-STD-690 (ER parts only). The manufacturer shall also establish a Statistical Process Control (SPC),

Part Per Million (PPM) and characterizing circuit reactance systems that meets the requirements as

described in 3.3.1 and 3.3.2, respectively.

3.3.1 SPC system. As part of the overall MIL-STD-790 QPL system, the manufacturer shall establish a

SPC system that meets the requirements of EIA-557. Typical manufacturing processes for application of

SPC include dc resistance values, cap/lead attachment, trimming, encapsulation, and weld strength. In

addition, the manufacturer shall demonstrate resistance temperature characteristic (RTC) control in the

process.

3.3.2 PPM system. As part of the overall MIL-STD-790 QPL system, the manufacturer shall establish a

PPM system for assessing the average outgoing quality of lots in accordance with EIA-554-1 and 4.6.4.

Data exclusion, in accordance with EIA-554-1, may be used with approval of the qualifying activity. The

PPM system shall identify the PPM rate at the end of each month and shall be based on a six month

moving average. PPM and dc resistance shall be assessed for each style. Style reporting may include

both non-ER and ER style combinations.