www.vishay.com 11 temperature sensitive resistors vishay ULTRONIX document number: 69105 revision 09-oct-00 temperature sensitive resistors large ? r/ ? t features ? custom tcr to 2% tolerance ? absolute resistance tolerance to 0.1% ? fast thermal transition ? physical configurations to your specifications ? excellent tcr linearity ? excellent repeatability although precision wirewound resistors are usually selected for their tight tolerance and low tcr capabilities, it is sometimes necessary to use a high-tcr resistor to compensate for other circuit components which exhibit negative tc. also, because of their high reliability and linear resistance vs. temperature characteristics, high-positive- tcr resistive devices are frequently used to measure temperature or provide temperature reference for thermocouples. high tcr resistors are offered in our standard packages, (page 5 & 6), and special packages are available to meet your design specifications. if you have a unique application or package requirement, our applications engineering department is ready to assist in your design. wire alloy temperature coefficient common (ppm/ c) resistivity maximum trade name (ohms/cmf) resistance or equivalent C 55 c to + 25 c+ 25 c to + 125 c factor* evanohm ? + 5 10 + 5 10 800 1.00 3520 ni/tophet d ? + 380 40 + 400 40 600 0.76 90 alloy + 450 50 + 450 50 90 0.11 60 alloy + 700 200 + 700 200 60 0.08 316 s.s. + 850 80 + 850 80 470 0.59 304 s.s. + 1000 100 + 1000 100 420 0.53 30 alloy + 1400 300 + 1400 300 30 0.04 42% ni fe + 2600 200 + 2600 200 420 0.53 kovar ? + 3500 300 + 3500 300 294 0.37 balco 1 ? + 3900 300 + 4500 400 120 0.15 nickel 270 1 + 5000 300 + 6000 300 42 0.05 note: special rtc s available by combining alloys *to obtain maximum resistance available, multiply the maximum value for the particular resistor style by the maximum resistance factor. ? registered trademark of carpenter technology corporation, reading, pa, usa. basic information required for design and quotation resistor description ? style/size/mechanical description, if special ? resistance value at a given temperature ? tolerance at the same temperature ? amount of variation per c and temperature range ? linearity and tolerance on tcr ? power rating desired the table below lists several common resistance-wire alloys according to the tcr. there are many alloys available with special tcrs within this range. availability of alloys, however, does not limit the ability to obtain other special tcrs up to + 6000 ppm/ c. intermediate values can be obtained by utilizing various manufacturing techniques and by selecting and combining resistance wires of various alloys. table 7 - wire selection
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