MIL-PRF-39017 Resistors, Fixed, Film \(Insulated\), Nonestablished Reliability, And Established Reliability, General Specification ForThis specification covers the general requirements for nonestablished reliability \(non-ER\) and established reliability \(ER\), insulated, film, fixed resistors. These resistors are capable of full load operation at an ambient temperature of 70 Degrees C and have a resistance temperature characteristic of 100 parts per million \(PPM\) and 350 PPM per degree Celsius \(PPM/Degrees C\). The ER resistors have life failure rate \(FR\) levels ranging from 1.0 percent to 0.001 percent per 1,000 hours \(see 1.2.1.4\). These FR levels are established at a 60 percent confidence level on the basis of life tests. Designers are CAUTIONED on using these resistors in high power pulse applications \(see 6.13.2\).

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MIL-PRF-39017G

4.8.19 High temperature exposure (see 3.25).

a. Mounting: Resistors shall be mounted by means other than soldering or may be placed in trays.

When trays are used, they must be designed to present a minimum construction to the airstream;

so that the specified ambient temperature can be achieved throughout the chamber.

b. Initial measurements: DC resistors shall be measured as specified in 4.8.3 at room ambient

conditions.

Procedure: Following initial resistance measurements resistors shall placed in a chamber

maintained at 150�C, +15�C, -0�C for 100 PPM (125�C +15�C, -0�C for resistance temperature

coefficient of 350 PPM) (see 3.1) for a period of 2,000 hours +72 hours, -0 hours with no load.

d. Measurements during test: At 250 hours +48 hours, -0 hours, resistor shall be removed from

chamber and permitted to stabilize at room temperature and within 6 hours after removal, the dc

resistance shall be measured as specified in 4.8.3. Resistors shall be examined for evidence of

mechanical damage.

e. Final measurements: After removal from the test chamber resistors shall be permitted to stabilize

at room ambient temperatures and within 6 hours after removal, the dc resistance shall be

measured as specified in 4.8.3. Resistors shall be examined for evidence of mechanical

damage.

4.8.20 Fungus (see 3.26). Resistors shall be tested in accordance with method 508 of MIL-STD-810.

4.8.21 Aqueous-extract-conductivity test procedure (see 3.5.1).

4.8.21.1 Outline of method. The sample is extracted with hot water. The conductivity of electrolytic

surface contaminants is measures with a conductivity bridge or resistance indicator and compared with

deionized or distilled water blank.

4.8.21.2 Apparatus.

4.8.21.2.1 Conductivity bridge. A conductivity bridge or resistance indicator shall be used with the

capability of measuring resistance up to at least 2 megohms. Within the range of 0.3 megohms to 1

megohm inclusive, the accuracy of adjustment shall be within 5 percent.

4.8.21.2.2 Constant temperature bath. A water bath maintained at 25�C �0.5�C. If the conductivity

bridge as described in 4.8.21.2.1 is cable of automatic temperature compensation to within �0.5�C, the

water bath temperature shall be 25�C �0.5�C.

4.8.21.2.3. Beakers. Two acid and alkali-resistant glass, 125 milliliter (ml), tall form beakers or any

beakers of such dimension that the dip-type cell is immersed in 100 ml of liquid contained therein, the

electrodes are fully covered.