scope:

This specification covers the general requirements for power type, wirewound, fixed resistors which utilize the principle of heat dissipation through a metal mounting surface. The resistors have an initial resistance tolerance of ±1 percent and a resistance-temperature characteristic of ±0.0030 percent per °C (30 parts per million (30 ppm)) for resistance values of 2,000 ohms and higher and ±0.0050 percent per °C (50 ppm) for resistance values under 2,000 ohms. They are not suitable for application where the alternating-current (ac) characteristics are of critical importance; however, provisions have been made to minimize the inductance.

The type designation shall be in the following form, and as specified (see 3.1 and 6.1):

The style is identified by the two-letter symbol "RE" followed by a two-digit number; the letters identify chassis-mounted, power-type, wirewound, fixed resistors, and the number identifies the size and power rating of the resistor.

The characteristic is identified by a style letter which identifies the maximum continuous operating temperature, and inductive (G) or noninductive (N) method of winding in accordance with table I. TABLE I. Characteristic.

Symbol Method of winding Maximum continuous operating temperature ------------------------------------------------------------------------------------ °C G - - - - - - Inductive 275 N - - - - - - Noninductive 275

The nominal resistance value expressed in ohms is identified by a four-digit number; the first three digits represent significant figures and the last digit specifies the number of zeros to follow. Where fractional values of an ohm, and values of less than 100 ohms, are required, the letter "R" is substituted for one of the significant digits to represent the decimal point. When the letter "R" is used, the succeeding digits become significant. The following are examples of symbols for resistance values:

R100 = 0.10 ohm 1R00 = 1.0 ohm 10R0 = 10 ohms 1000 = 100 ohms 1001 = 1,000 ohmm 1002 = 10,000 ohms

Minimum and maximum resistance values shall be as specified (see 3.1 ). The standard resistance values for every decade shall follow in the sequence demonstrated for 1 to 10 decade (see table II). TABLE II. Standard resistance values for 1 to 10 decade. 1/

1.00 1.47 2. 3.16 4.64 6.81 1.02 1.50 2. 3.24 4.75 6.98 1.05 1.54 2. 3.32 4.87 7.15 1.07 1.58 2. 3.40 4.99 7.32 1.10 1.62 2. 3.48 5.11 7.50 1.13 1.65 2. 3.57 5.23 7.68 1.15 1.69 2. 3.65 5.36 7.87 1.18 1.74 2. 3.74 5.49 8.06 1.21 1.78 2. 3.83 5.62 8.25 1.24 1.82 2. 3.92 5.76 8.45 1.27 1.87 2. 4.02 5.90 8.66 1.30 1.91 2. 4.12 6.04 8.87 1.33 1.96 2. 4.22 6.19 9.09 1.37 2.00 2. 4.32 6.34 9.31 1.40 2.05 3.01 4.42 6.49 9.53 1.43 2.10 3.09 4.53 6.65 9.76 1/ Values not listed will be considered nonstandard.