Search for... Search rrttii--pprreecciissiioonn--iinntteerrcchhaannggeeaabbllee Accu-Curve Precision Interchangeable Thermistors ACCU-Curve Precision Thermistors Ametherm manufactures precision resistance-temperature matched ACCU-CURVE thermistors. These devices offer interchangeability over a broad temperature range and eliminate the need to individually calibrate or provide circuit compensation for part variability. Accurate temperature measurement to 0.2C is available over the 0C to 70C temperature range. Standard ohmic values at 25C range from 2,252 to 100,000 ohms. ACCU-CURVE Selection Considerations Determine Resistance Value & Temperature Coefficient Review Power Dissipation Select Temperature Range Review Thermal Time Constant Request Free Samples Have A Question Request Free Samples Have A Question Avaliable at: Applications There are numerous ways of measuring temperature electronically. Improvements in thermistor technology, coupled with the introduction of integrated circuitry, have made precision temperature measurement systems very cost effective Microprocessors, A/D converters, interface electronics and displays are readily available. Circuit designs with built-in thermistor resistance-temperature algorithms have gained wide spread acceptance in precision temperature metrology. Ametherms s ACCU-CURVE style thermistors are used in many applications that require a high degree of accuracy and reliability. Some of the most popular applications of NTC ACCU-CURVE thermistors include: Temperature Measurement & Control Temperature Sensors Interchangeable ACCU-CURVE NTC thermistors are usually selected when a high degree of measurement accuracy is required over a wide temperature range. By modifying the Alpha equation the resistance and temperature tolerances can be calculated for various temperature intervals. Because thermistors are non-linear with respect to their resistance-temperature characteristics, Alpha therefore is non-linear across their resistance-temperature range. As an example, a thermistor material curve with an Alpha of -4.4%/C 25C will have an Alpha of -3.8%/C 50C. For practical applications we recommend that the standardized R/T curves be used. Ametherm ACCU-CURVE thermistors can dissipate 1mW/C. As a result, the possibility of error induced by excessive current flow, which would defeat the level of accuracy these devices are capable of representing, may exist in some circuits. To prevent this type of error, Ametherm recommends that circuit design engineers select the highest R value their circuit will tolerate for applications > 5 Volts to minimize any self-heating of the thermistor device. Refer to the ACCU-CURVE Specifications table for resistance values and temperature tolerances. Ametherm offers two standard R/T curves, &, with temperature coefficients of resistance of -4.4%/C and -4.7%/C, and Beta () values of 3965K and 4250K. To determine the nominal resistance value of a thermistor at a specified temperature, multiply its resistance at 25C value by the corresponding RT/R25 value for the desired temperature and applicable R-T curve from the ACCU-CURVE. Selection Considerations for NTC ACCU-CURVE Devices Interchangeable ACCU-CURVE NTC thermistors are usually selected when a high degree of measurement converted by Web2PDFConvert.comaccuracy is required over a wide temperature range. By modifying the Alpha equation the resistance and temperature tolerances can be calculated for various temperature intervals. Because thermistors are non-linear with respect to their resistance-temperature characteristics, Alpha therefore is non-linear across their resistance-temperature range. As an example, a thermistor material curve with an Alpha of -4.4%/C 25C will have an Alpha of -3.8%/C 50C. For practical applications we recommend that the standardized R/T curves be used. Ametherm ACCU-CURVE thermistors can dissipate 1mW/C. As a result, the possibility of error induced by excessive current flow, which would defeat the level of accuracy these devices are capable of representing, may exist in some circuits. To prevent this type of error, Ametherm recommends that circuit design engineers select the highest R value their circuit will tolerate for applications > 5 Volts to minimize any self-heating of the thermistor device. Refer to the ACCU-CURVE Specifications table for resistance values and temperature tolerances. Ametherm offers two standard R/T curves, &, with temperature coefficients of resistance () of -4.4%/C and -4.7%/C, and Beta () values of 3965K and 4250K. To determine the nominal resistance value of a thermistor at a specified temperature, multiply its resistance at 25C value by the corresponding RT/R25 value for the desired temperature and applicable R-T curve from the ACCU-CURVEResistance/Temperature Conversion Table. ACCU-CURVESpecifications Temperature Tolerance from 0 C to 70 C Resistance Color 0.2 C 0.5 C 1.0 C 25 C (ohms) Code Part Number Part Number Part Number 2,252 ACC-001 ACC-011 ACC-021 Brown 3,000 ACC-002 ACC-012 ACC-022 Red 5,000 ACC-003 ACC-013 ACC-023 Orange 10,000 ACC-004 ACC-014 ACC-024 Yellow 30,000 ACW-005 ACW-015 ACW-025 Green 50,000 ACW-006 ACW-016 ACW-026 Blue 100,000 ACW-007 ACW-017 ACW-027 Violet ACCU-CURVEResistance/Temperature Table CURVES CURVES TEMP 2,252 3,000 5,000 10,000 30,000 50,000 100,000 (C) ohm s ohms ohm s ohm s ohm s ohm s ohms 25C 25C 25C 25C 25C 25C 25C -40 75,780 100,950 168,250 336,500 1,204,600 2,007,700 4,015,500 -30 39,860 53,100 88,500 177,000 619,200 1,032,000 2,064,000 -20 21,860 29,121 48,535 97,070 331,030 551,720 110,3400 -10 12,460 16,599 27,665 55,330 183,560 305,940 611,870 0 7,352.8 9,795.0 16,325 32,650 105,310 175,510 351,020 10 4,481.5 5,970.0 9,950.0 19,900 62,354 103,920 207,850 20 2,812.8 3,747.0 6,245.0 12,490 38,022 63,370 126,740 25 2,252.0 3,000.0 5,000.0 10,000 30,000 50,000 100,000 30 1,814.4 2,417.1 4,028.5 8,057.0 23,827 39,711 79,422 40 1,199.6 1,598.1 2,663.3 5,327.0 15,314 25,524 51,048 50 811.40 1,080.9 1,801.5 3,603.0 10,077 16,795 33,591 60 560.30 746.40 1,244.0 2,488.0 6,777.1 11,295 22,590 70 394.55 525.60 876.00 1,752.0 4,650.5 7,750.9 15,502 80 282.63 376.50 627.50 1,255.0 3,251.2 5,418.7 10,837 90 206.13 274.59 457.65 915.30 2,312.3 3,853.9 7,707.7 100 152.75 203.49 339.15 678.30 1,670.8 2,784.6 5,569.3 110 114.92 153.09 255.15 510.30 1,224.9 2,041.5 4,082.9 120 87.671 116.79 194.65 389.30 909.99 1,516.7 3,033.3 130 67.770 90.279 150.47 300.93 684.31 1,140.5 2,281.0 140 52.983 70.581 117.64 235.27 520.30 867.16 1,734.3 150 41.881 55.791 92.985 185.97 399.56 665.94 1,331.9 The ACCU-CURVE device can also be supplied with 32 AWG solid Teflon insulated leads of 3, 6, 9 and 12 inches in length. contact Ametherm applications engineering for additional information. Warning: Use Heat sinks when soldering to Thermistor Leads. ACCU-CURVEResistance/Temperature Conversion Tables ACCX-0XX ACWX-0XX CURVE CURVE converted by Web2PDFConvert.com