NPFC - MIL-R-27208
RESISTOR, VARIABLE, WIRE WOUND, NONPRECISION GENERAL SPECIFICATION FOR
|Publication Date:||24 August 1992|
This specification covers the general requirements for multiturn, lead-screw actuated and single turn wire-wound, variable resistors with a contact bearing uniformly over the entire surface of the entire resistive element, wound linearly, when positioned by an actuator. These resistors are capable of full load operation (where maximum resistance is engaged) at a maximum ambient temperature of 85°C, and are suitable for continuous operation when properly derated, at a maximum temperature of 150°C (see figure 2). These resistors have a resistance tolerance of ±5 percent (see 3.1).
The PIN shall be in the following form and as specified (see 3.1 and 6.2):
The style is identified by the two-letter symbol "RT" followed by a two-digit number. The letters identify adjustment type, wire-wound, variable resistors and the number identifies the physical size.
The resistance temperature characteristic of the completed resistor is identified by a single letter in accordance with table I. TABLE I. Characteristics.
Symbol Maximum resistance Parts per million
temperature characteristic per °C (ppm) 1/
in percent per °C 1/
Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: 2750 LOG/ESP Gentile Station, 1060 Hamilton Street, Dayton, OH 45444-5400 by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.
The temperature characteristic is identified by a single digit number in accordance with table II. TABLE II. Temperature characteristic.
Maximum resistance Parts per million
Symbol temperature characteristic per °C (ppm)
in percent per °C
The terminals are identified by a single letter in accordance with table III. TABLE III. Terminals.
Symbol Type of terminal
The nominal resistance 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:
100 = 10 ohms 101 = 100 ohms 102 = 1,000 ohms
The PIN RT10C2P102 signifies:
RT10 - Adjustment type, wire-wound, variable resistor of the dimensions specified (see 3.1). C - Having a resistance temperature characteristic of 0.005 percent ±50 ppm) per °C. 2 - Having a temperature characteristic capable of operation at 85°C maximum and derated, at 150°C maximum (see 3.5). P - Having printed circuit pins. 102 - Having a nominal total resistance value of 1,000 ohms.
Resistors covered by this specification are intended for use in electronic equipment, and are used for matching, balancing, and adjusting circuit variables in computers, telemetering equipment,... View More
Resistors covered by this specification are intended for use in electronic equipment, and are used for matching, balancing, and adjusting circuit variables in computers, telemetering equipment, and other applications.View Less