MIL-R-93 Resistors, Fixed, Wire-Wound, Accurate, General Specification ForThis specification covers the general requirements for accurate, wire-wound, fixed resistors having a maximum resistance tolerance of 1 percent, with the winding protected against high humidity. The resistors are rated for continuous full load operation at any ambient temperature up to 125 Degrees C, and derated up to 145 Degrees C. They are not capable for application where alternating current ac characteristics are of critical importance. Performance characteristics are in accordance with table I.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 - 26 - 27 - 28 - 29

MIL-R-93F

3.15  Life.  When resistors are tested as specified in 4.7.11, there shall be no evidence of mechanical damage to the resistance element, coating, or enclosure.  The change in resistance between the initial resistance measurement and any succeeding measurement shall not exceed ±(0.5 percent +0.05 ohm).

3.16  Resistance temperature characteristic.  When resistors are tested as specified in 4.7.12, the resistance temperature characteristic referred to an ambient temperature of 25°C shall not exceed the value specified in table III.

3.17  Low temperature storage.  When resistors are tested as specified in 4.7.13, there shall be no evidence of mechanical damage.  The change in resistance between the initial and final resistance measurements at 25°C ±5°C shall not exceed ±(0.2 percent +0.05 ohm).

3.18  Low temperature operation.  When resistors are tested as specified in 4.7.14, there shall be no evidence of mechanical damage.  The change in resistance between the initial and final resistance measurements at 25°C ±5°C shall not exceed ±(0.25 percent +0.05 ohm).

3.19  High temperature exposure.  When resistors are tested as specified in 4.7.15, there shall be no damage or loosening under a mounting bolt, where applicable.  The change in resistance shall not exceed ±(0.5 percent +0.05 ohm).

3.20  Shock, specified pulse.  When resistors are tested as specified in 4.7.16, there shall be no evidence of mechanical or electrical damage.  The change in resistance shall not exceed ±(0.1 percent

+0.05 ohm).  There shall be no electrical discontinuity during the test.

3.21  Vibration, high frequency.  When resistors are tested as specified in 4.7.17, there shall be no evidence of mechanical or electrical damage.  The change in resistance shall not exceed ±(0.1 percent

+0.05 ohm).  There shall be no electrical discontinuity during the test.

3.22  Fungus.  All external materials shall be non-nutrient to fungus growth or shall be treated to retard fungus growth.  The supplier shall verify by certification that all external materials are fungus resistant or shall test the resistors as specified in 4.7.18.  There shall be no evidence of fungus growth.

3.23  Marking.  Resistors shall be marked with the PIN (see 1.2.1), and the manufacturer's name, trademark, or code symbol.  If space permits, the resistance value in absolute ohms, the initial resistance tolerance, the rated or maximum voltage or the power rating, as applicable, shall also be marked.  There shall be no space between the symbols which comprise the type designation.  If lack of space requires it, the PIN shall be divided between the resistance temperature characteristic letter and the first digit of the resistance value, as shown in the following example:

RB52CE

127010

Marking shall remain legible at the end of all tests.

8