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

4.8.15 Moisture resistance (see 3.21). Resistors shall be tested in accordance with method 106 of

MIL-STD-202. The following details and exceptions shall apply:

a. Mounting: Resistors shall be soldered by their leads to standoff insulators on a panel so that there

will be at least 1 inch of free air space around each resistor1. The spacing of the mounts shall be

such that the length of each resistor lead is 0.375 inch �0.063 inch when measured from the edge

of the supporting terminal to the resistor body. Resistor leads may be formed, if necessary, so as

not to compromise the seal of the resistor. In addition, one-half of the sample units shall be

covered with a V-shape metal strap whose width is equal to the length of the resistor body as

indicated on figure 4. The strap shall be made of a corrosion-resistant metal and shall be kept in

contact with the resistor body by supporting the body as indicated on figure 4, with a

nonconducting, noncorrosive support whose width is less than that of the body and which shall not

act as a moisture trap. The mounting straps may be individual for each resistor or continuous for

all resistors. These resistors with strapping shall be subjected to the polarization voltage.

b. Initial measurement: Following thermal stabilization (within 30 minutes after resistors have been

removed from drying oven), dc resistance shall be measured as specified in 4.8.3.

Polarization and loading voltage:

(1) Polarization voltage: During steps 1 to 6 inclusive, a 100 volt dc potential shall be applied

only to resistors which have a polarizing strap. This potential shall be applied with the

positive lead connected to the resistor terminals tied together, and the negative lead

connected to the polarizing strap.

(2) Loading voltage: During the first 2 hours of steps 1 and 4, a dc test potential equivalent to

100 percent rated dc continuous working voltage shall be applied to the resistors which do

not have the polarizing strap specified in 4.8.15a.

d. Subcycle: Step 7a shall be performed during any five of the first nine cycles. Step 7b shall not

be applicable. All polarizing straps shall be removed to perform step 7a and then be replaced

prior to returning the resistors to the humidity chamber.

e. Final measurements: Upon completion of step 6 of the final cycle, the resistors shall be held at

the high humidity condition and a temperature of 25�C �2�C for a period of 1 hour 30 minutes to 3

hours 30 minutes. Resistors shall be removed from the chamber and within 30 minutes, without

any additional handling, the dc resistance, dielectric withstanding voltage, and insulation

resistance shall be measured in that order, as specified in 4.8.3, 4.8.12.1, and 4.8.13,

respectively. The straps shown in figure 4 shall be used for these measurements. Sample units

shall not be subjected to forced air drying prior to or during these final measurements

Examination after test: Resistors shall be examined for evidence of mechanical damage.

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1 Standoff insulators of polytetrafluoroethylene are preferred for use with resistors of high resistance

values.