scope:

This specification covers the detail requirements for styles RW20, RW21, RW22, RW23, and RW24 resistors.

The type designation shall be in the following form:

The style is identified by the two-letter symbol "RW" followed by a two-digit number; the letters identify power type, wire-wound, fixed resistors, and the number identifies the size, wattage rating, and construction of the resistors.

The characteristic is identified by a single letter that identifies the maximum continuous operating temperature (surface hot spot), the minimum insulation resistance value at the end of the moisture resistance test, and the resistance temperature characteristic in accordance with table I. TABLE I. Characteristic.

Symbol Maximum continuous Minimum insulation Resistance-temperature operating resistance at end of characteristic temperature 1/ moisture resistance test (percent per degree C) ------------------------------------------------------------------------------------------------------ °C Megohms V - - - 350 100 ±.040 for resistance values below 20 ohms. ±.026 for resistance values of 20 ohms and above 1/ This temperature is also the maximum permissible hot-spot surface temperature.

The nominal resistance 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 zeroes to follow. Where fractional values of an ohm are required, the letter "R" shall be substituted for one of the significant digits to represent the decimal point. When the letter "R" is used, succeeding digits of the group represent significant figures as shown in the following example:

R10 = 0.1 ohm 1R0 = 1.0 ohm

The letter "T" when added at the end of the type designation shall denote that the resistor is center-tapped.