scope:

This specification covers the general requirements for precision, wire-wound, variable resistors whose electrical output (in terms of percent of applied voltage) are linear or nonlinear with respect to the angular position of the operating shaft. This specification includes requirements for linear and nonlinear, single turn and multiturn, single-section (cup) and multi-section variable resistors. These resistors are capable of full-load operation at maximum ambient temperatures of 70° and 85° C and are suitable for continuous operation, when properly derated, to maximum temperatures of 125° and 150° C, respectively (see figure 9, 3.1, and 6.1). This specification includes procedures and requirements for the procurement of category I, category II, and category III precision resistors. Procedures are provided for qualification of a manufacturer's family of products of resistors through the qualification testing of representative standard product, and the inspection and approval of the quality assurance program employed on the manufacturer's production line. Family of products approval covers a prescribed limited variety of products similar to resistors covered by detail specifications, submitted for qualification, and manufactured on the same production line. This specification specifies characteristics and requirements preferred for military equipments. Detail specifications describe category I resistors of preferred sizes, ratings and requirements. Category I resistors shall be ordered as specified in 6.1.1. Resistors which deviate from these category I resistors because of electrical, mechanical or environmental characteristics or requirements, not specified herein, and which are within the limits of similarity to corresponding qualified category I resistors (see 4.4.7) are considered qualified under the family of products qualification and are referred to as category II units. These resistors shall be ordered as specified in 6.1.2. Procurement of resistors whose design, ratings or other requirements exceed the limits of family of products qualification shall be considered category III items, and shall be procured in accordance with 6.1.3.