MIL-R-10509 Resistors, Fixed, Film High Stability General Specification ForThis specification covers the general requirements for high-stability, film, fixed resistors that are relatively stable with respect to time under environmental condition

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MIL-R-10509J

4.7.11 Moisture resistance (see 3.16). Resistors shall be tested in accordance with method 106 of

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

a. Mounting: Soldering by their leads to rigid mounts or terminal lugs. The spacing of the mounts or terminal lugs shall be such that the length of each resistor lead is approximately .375 inch (9.53 mm) when measured from the edge of the supporting terminal to the resistor body. One half of the sample units shall be covered with a V-shaped metal strap whose width is equal to that of the resistor body in indicated in figure 3. The strap shall be made from corrosion resistant metal and shall be kept in contact with the resistor body by supporting the body as indicated in figure 3, with

a nonconducting, noncorrosive support whose width is less than that of the resistor body and which will not act as a moisture trap. The mounting straps may be individual for each resistor or continuous for all resistors.

FIGURE 3. Mounting straps for all styles.

b. Initial measurement: Immediately following the initial drying period, dc resistance shall be measured as specified in 4.7.2.

c. Polarization and loading voltage: The resistance value selected shall be divided equally as possible for polarization and load.

(1) Polarization: During steps 1 to 6 inclusive, a dc potential of 50 volts for styles RN50 , and 100 volts for all other styles shall be applied only to those 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 straps.

(2) Loading voltage: During the first 2 hours of steps 1 and 4, a dc test potential equivalent to 100 percent rated wattage but not exceeding the maximum rated voltage shall be applied to those resistors which do not have the polarizing strap specified in 4.7.11a.

d. Subcycle 7b shall not be applicable. Step 7a shall be performed during any five of the first nine cycles only. All polarization straps shall be removed to perform steps 7a and shall then be replaced prior to starting the next cycle.