DLA - MIL-R-39035C
RESISTORS, VARIABLE, NONWIRE WOUND (ADJUSTMENT TYPE), NONESTABLISHED RELIABILITY, AND ESTABLISHED RELIABILITY, GENERAL SPECIFICATION FOR
|Publication Date:||11 October 1991|
This specification covers the general requirements for multiturn lead-screw actuated, and single-turn, nonwire-wound, variable resistors with a contact bearing uniformly over the surface of the entire resistive element, when positioned by an actuator. These resistors are capable of full-load operation (when the maximum resistance is engaged), at a maximum temperature of 150°C, with a resistance tolerance of ±10 percent. The resistors will have life failure rate levels ranging from 1.0 to 0.001 percent per 1,000 hours (see 188.8.131.52). These failure rate levels are established at a 60-percent confidence level maintained at 10-percent producer's risk on the basis of the life tests. The failure rate level, identified by the appropriate symbol is referred to operation at full rated voltage at 85°C, with a permissible change in resistance of ±5 percent as the criteria for failure. Table I of supplement 1 provides a summary of performance characteristics for these resistors. A part per million (PPM) quality system is used for documenting and reporting the average outgoing quality of resistors supplied to this specification. Statistical process control (SPC) techniques are required in the manufacturing process to minimize variation in production of resistors supplied to the requirements of this specification.
The PIN shall be in the following form, and as specified (see 3.1). Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Electronic Support Division, AFLC, 2750th ABW/ESP, Bldg 2, Gentile Air Force Station, Dayton, OH 45444-4500 by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.
The style is identified by the three letter symbol "RJR" followed by a two-digit number; the letters identify established reliability, adjustment type, nonwire-wound variable resistors, and the number identifies the physical size.
The characteristic is identified by a single letter which identifies the resistance-temperatu
Symbol Maximum resistance Maximum ambient Maximum ambient
temperature characteristic temperature at operating
(referred to 25°C rated wattage temperature
The terminals are identified by a single letter in accordance with table II. TABLE II. Terminals.
Symbol Type of terminal
The nominal total value expressed in ohms is identified by a three-digit number; the first two digits represent significant figures and the last digit specifies the number of zeros to follow. The following are examples of symbols for resistance values.
101 = 100 ohms 102 = 1,000 ohms
The life failure rate level designation as shown in table III is signified by a single letter (M, P, R, or S), which identifies the life failure-rate level for which the resistor is qualified (see 4.5). TABLE III. Failure rate designations.
Failure-rate level Failure rate
designation percent/1,000 hours
The PIN "RJR24 F P 102 M" signifies:
RJR24 - Adjustment type, resistor variable non-wire-wound (established reliability) of the dimensions specified (see 3.1). F - Having a characteristic signifying a maximum resistance temperature characteristic of ±0.010 percent per °C (±100 PPM) and a capability of operating at rated wattage of 85°C maximum and when derated at 150°C maximum (see figure 2). P - Having printed circuit pins. 102 - Having a nominal resistance value of 1,000 ohms. M - Having a failure rate level of 1.0 percent per 1,000 hours.
Resistors covered by this specification are intended for use in electronic equipment, and are used for matching, balancing, adjusting circuit variables in computers, telemetering equipment, and... View More
Resistors covered by this specification are intended for use in electronic equipment, and are used for matching, balancing, adjusting circuit variables in computers, telemetering equipment, and other critical applications.View Less