B-2

Beryllia Core, Silicone Coated Power Resistors MIL-R-26 (RW) & Commercial Industrial Styles B Series IRC "B" Series resistors offer power ratings up to 4 times highere than standard power wirewound resistors of equal size. This is made possible due to a finer heat dissipation pattern. The Series "B" resistors will equal the same stability and environmental requirements of lower rated conventional resistors. Electrical Data Heat Dissipation Power Rating Power to Size Ratio Wattage Beryllia core provides finest possible pattern Up to 4x higher than conventional resistors, depending upon physical size 35% to 400% greater than standard silicone coated types 1 watt to 18 watts ± 20 ppm/°C 10Ωup ± 50 ppm/°C 1Ω to 9.9Ω ± 400 ppm/°C 0.5Ω to 0.499Ω ± 650 ppm/°C 0.1Ω to 0.499Ω 22 special T.C.’s available from -20 ppm to +6000 ppm ± 1% to + 0.1% From .1 to 150K Special high temperature silicone coating, impervious to moisture, salt water immersion, and abrasion Tinned copperweld is standard 500 volts AC for B-1, B-2, B-3; all others 1000 volts 5000 megaohms minimum dry Standard Temperature Coefficients Special Temperature Coefficients Tolerance Resistance Values Coating Leads Dielectric Strength Insulation Resistance General Note IRC reserves the right to make changes in product specification without notice or liability. All information is subject to IRC’s own data and is considered accurate at time of going to print. Wire and Film Technologies Division • 4222 South Staples Street • Corpus Christi Texas 78411 USA Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com A subsidiary of TT electronics plc B Series Issue September 2008 Sheet 1 of 3 Beryllia Core, Silicone Coated Power Resistors MIL-R-26 (RW) & Commercial Industrial Styles Physical Data A Length B C dia. D Lead Length 1.375 (34.9 mm) Minimum IRC Style U B-1 B-2 B-3 B-5 B-5A B-5C B-6 B-10 B-12 B-15 Rated Wattage V Dimensions Length A .250 ± .032 Diameter B .085 ± .020 .078 ± .032 .094 ± .032 .188 ± .032 .188 ± .032 .218 ± .032 .250 ± .032 .312 ± .032 .312 ± .032 .375 ± .032 Lead Diam. C AWG #24 #24 #24 #20 #20 #18 #18 #18 #18 #18 IRC Max Resistance 2.0K 3.4K 6.5K 22K 34K 18K 40K 54K 75K 150K Metric Dimensions Dimensions Length A 6.4 ± 0.8 7.9 ± 1.6 10.3 ± 0.8 14.3 ± 1.6 20.6 ± 1.6 12.7 ± 1.6 15.7 ± 1.6 22.2 ± 1.6 31 ± 1.6 45.2 ± 1.6 Diameter B 2.2 + 0.5 2.0 + .08 2.4 + .08 4.8 + .08 4.8 + .08 5.5 + .08 6.4 + .08 7.9 + .08 7.9 + .08 7.9 + .08 Lead Dia. C mm 0.5 0.5 0.5 0.8 0.8 1.0 1.0 1.0 1.0 1.0 1.0 1.5 2.25 4.0 4.5 5.0 6.0 7.0 10.0 15.0 2.0 2.75 5.0 6.5 7.0 8.0 10.0 12.0 18.0 .312 ± .062 .406 ± .032 .562 ± .062 .812 ± .062 .500 ± .062 .625 ± .062 .875 ± .062 1.218 ± .062 1.780 ± .062 Wire and Film Technologies Division • 4222 South Staples Street • Corpus Christi Texas 78411 USA Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com B Series Issue September 2008 Sheet 2 of 3 Beryllia Core, Silicone Coated Power Resistors MIL-R-26 (RW) & Commercial Industrial Styles Power Derating Curve 120 Percent of Power Rating 100 80 Char. V 60 40 Char. U 20 0 25 75 125 175 225 275 350 Ambient Temperature (°C) Derating Ambient Temperature: Operating temperature range of -55°C to +350°C. Higher temperatures require derating as illustrated. Stability: Resistance chance is 1/2 or less than that of conventional power resistors when operated at the same wattage. Characteristic U 1. 275°C maximum hotspot temperature. 2. 5% maximum ∆R for 2000 hour load life. Characteristic U: 1. 350°C maximum hotspot temperature. 2. 3% maximum ∆R for 2000 hour load life. Wire and Film Technologies Division • 4222 South Staples Street • Corpus Christi Texas 78411 USA Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com B Series Issue September 2008 Sheet 3 of 3