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

3.7 Short time overload. When resistors are tested as specified in 4.8.3, there shall be no evidence of

arcing, burning, or charring. The change in resistance shall not exceed 0.01 percent for resistance values

of 10 ohms and above, and �(0.01 percent +.01 ohm) for resistance values less than 10 ohms.

3.8 Thermal shock. When resistors are tested as specified in 4.8.4, there shall be no evidence of

mechanical damage. The change in resistance shall not exceed �0.05 percent for resistance values of 10

ohms and above, and �(0.05 percent +0.01 ohm) for values less than 10 ohms.

3.9 DC resistance. When resistors are tested as specified in 4.8.5, the dc resistance shall be

expressed in absolute ohms (see 1.2.1.3), and shall be within the specified initial tolerance of the nominal

resistance (1.2.1.4).

3.9.1 Resistance value deviations. All maximum deviations as specified in this section are to be

considered absolute limits with the exception of the contact resistance adjustments.

3.10 Solderability (applicable to "L" terminal only). When resistors are tested as specified in 4.8.6, they

shall meet the criteria for wire lead terminal evaluation in the test method.

3.11 Dielectric withstanding voltage. When resistors are tested as specified in 4.8.7, there shall be no

evidence of flashover, mechanical damage, arcing, or insulation breakdown. The change in resistance

shall not exceed �0.01 percent for resistance values of 10 ohms and above, and �(0.01 percent +0.01

ohm) for values less than 10 ohms.

3.12 Terminal strength. When resistors are tested as specified in 4.8.8, there shall be no break in the

wire-lead terminals, the resistance element shall remain securely connected mechanically and electrically

to the terminals in such a manner that the normal movement of the terminals shall not result in strain,

wear, or damage to the element, coating, or enclosure. The change in resistance shall not exceed �0.01

percent for resistance values of 10 ohms and above, and �(0.01 percent +0.01 ohm) for values less than

10 ohms.

3.13 Insulation resistance. When resistors are tested as specified in 4.8.9, the insulation resistance

shall not be less than 1,000 megohms.

3.14 Moisture resistance. When resistors are tested as specified in 4.8.10, there shall be no evidence

of breaking, cracking, spalling, or loosening of terminals or mounting hardware. The final insulation

resistance shall be not less than 100 megohms. The change in resistance shall not exceed � 0.1 percent

for resistance values of 10 ohms and above and �(0.1 percent +0.01 ohm) for values less than 10 ohms;

for style RBR71 the change in resistance shall not exceed �0.4 percent for resistance values of 10 ohms

and above, and �(0.4 percent +0.01) for values less than 10 ohms.

3.15 Resistance to soldering heat. When resistors are tested as specified in 4.8.11, there shall be no

evidence of mechanical damage. The change in resistance shall not exceed �0.01 percent for resistance

values of 10 ohms and above, and �(0.01 percent +0.01 ohm) for values less than 10 ohms.

3.16 Shock, specified pulse. When resistors are tested as specified in 4.8.12, there shall be no

evidence of mechanical or electrical damage. The change in resistance shall not exceed �0.01 percent

for resistance values of 10 ohms and above, and �(0.01 percent +0.01 ohm) for values less than 10

ohms.