document number: 33003 revision 11-feb-02 www.vishay.com 18 m, c, t vishay dale for technical questions, contact thermistor1@vishay .com features small size - conformally coated. wide resistance range. available in 11 different r-t curves. description models m, c, and t are conformally coated, leaded thermistors for standard pc board mounting or assembly in probes. the coating is baked-on phenolic for durability and long-term stability. models m and c have tinned solid copper leads. model t has solid nickel wires with teflon insulation to provide isolation when assembled in metal probes or housings. ntc thermistors,coated dimensions in inches [millimeters] ld diameter wire size type m awg 30: 0.0100 [0.254] type c awg 28: 0.0126 [0.320] type t awg 30: 0.0100 [0.254] ordering information 1 c 2001 f curve number model value tolerance first three digits are point match tolerances curve track tolerances significant. the last f = 1% @ 25 c a3 = 1 c0 c to + 70 c digit is the multiplier. g = 2% @ 25 c b3 = 0.5 c0 c to + 70 c (2000 ohm is illustrated.) h = 3% @ 25 c c3 = 0.2 c0 c to + 70 c j = 5% @ 25 c a2 = 1 c- 20 c to + 50 c k = 10% @ 25 c b2 = 0.5 c- 20 c to + 50 c c2 = 0.2 c- 20 c to + 50 c a4 = 1 c0 c to + 100 c b4 = 0.5 c0 c to + 100 c a5 = 1 c+ 25 c to + 90 c b5 = 0.5 c+ 25 c to + 90 c c5 = 0.2 c+ 25 c to + 90 c see following pages for tolerance a8 = 1 c0 c to + 50 c explanation and details b8 = 0.5 c0 c to + 50 c c8 = 0.2 c0 c to + 50 c tinned copper wire teflon insulated nickel wire body dia. max. body dia. max. 1.5 [36.1] min. clean lead length 1/4 nom. 24 0.5 [609.6 12.7]
www.vishay.com 19 m, c, t vishay dale document number: 33003 revision 11-feb-02 for technical questions, contact thermistor1@vishay .com 1234789121417 27 33 50 56 68 82 100 120 150 180 220 270 330 390 470 500 560 680 820 1k 1.2k 1.5k 1.8k 2.2k 2.7k 3.3k 3.9k 4.7k 5k 5.6k 6.8k 8.2k 10k 12k 15k 18k 22k 27k 33k 39k 47k 50k 56k 68k 82k 100k 120k 150k 180k 220k 270k 330k 390k 470k 500k 560k 680k 820k 1 meg r 25 (ohms) curve number selection guide for type m, c, and t thermistors note: 1. intermediate resistance values between the standard value series are available. size would be the same as the color grouping. 2. other body diameters available. bead diameter increases as res. decreases. (consult factory) 3. leaded series of thermistors includes additional styles: (consult factory) type b: 26awg lead, .0159 [.40] type f: 32awg lead, .008 [ .20] type e: 24awg lead, .020 [ .51] type d: 22awg lead, .025 [.64] type g: 20awg lead, .032 [ .81] type h: 18awg lead, .040 [1.02] maximum body diameter 0.125 [3.2] 0.110 [2.8] 0.095 [2.4] dissipation constant 2 - 3 mwatts/ c thermal time constant 6 - 14 seconds ntc thermistors, coated
document number: 33003 revision 11-feb-02 www.vishay.com 20 m, c, t vishay dale for technical questions, contact thermistor1@vishay .com description of thermistor tolerances the many applications of thermistors have mandated the need for two basic tolerance schemes for these products - curve tracking and point match thermistors. an example of the resistance tolerance at various temperatures for the two different tolerancing methods is described in the following graph: curve tracking tolerance : thermistors are calibrated at the high temperature of the curve track range and then final tested at the low temperature of the curve track range. this ensures that the thermistor will meet the specified temperature accuracy at every temperature within the desired temperature range. several temperature ranges are available and the accuracy of the thermistor may be 0.2 c, 0.5 c, and 1.0 c. the curve tracking temperature ranges and their code designators are shown in figure 1 and table 1. to specify, add the appropriate suffix from the following table to the part number. example: 1m1002-b3 = curve 1, 10 kilohms at + 25 c, curve tracking to 0.5 c from 0 c to + 70 c tolerances available for type m, c and t thermistors tolerance ( %) temperature ( c) 5% point match curve 1 c curve track curve 25 c 10 9 8 7 6 5 4 3 2 1 0 - 50 - 40 - 30 - 20 - 10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 a2 a8 a3 a5 a4 standard electrical specifications for curve tracking thermistors temp. range 0 c to + 70 c- 20 c to + 50 c0 c to + 100 c25 c to + 90 c0 c to + 50 c tolerance 1 c 0.5 c 0.2 c 1 c 0.5 c 0.2 c 1 c 0.5 c 0.2 c 1 c 0.5 c 0.2 c 1 c 0.5 c 0.2 c part no. suffix - a3 - b3 - c3 - a2 - b2 - c2 - a4 - b4 - c4 - a5 - b5 - c5 - a8 - b8 - c8 c 1 x x x xx x xxn/axx x xx x u 2 x x x xx x xxn/axx x xx x r 4 x x x xx x xxn/axx x xx x v 8 x x x xx x xxn/axx x xx x e 9 x x x xx x xxn/axx x xx x ntc thermistors, coated
www.vishay.com 21 m, c, t vishay dale document number: 33003 revision 11-feb-02 for technical questions, contact thermistor1@vishay .com the standard leaded thermistors are calibrated and tested at 25 c to a tolerance of 5% or 10%; however, tighter tolerance, point matched thermistors are readily available as are special point match temperatures to fit your application. since these thermistors have only one controlled point of reference ( the point match temperature ), the resistance at other temperatures is given by the "resistance vs temperature conversion tables" for the appropriate material curve. the resistance value at any temperature is the ratio factor times the resistance at 25 c. example: 1m1002-5, +70 c resistance = (resistance factor for curve 1 at 70 c is .1990) x (10000 ohm resistance at 25 c) = 1990 ohms. the tolerance of the resistance at any temperature is described by figure 2. point match resistance tolerances at temperatures other than 25? are not the same as the calibration temperature. this difference is presented in figure 2. the tolerance at any given temperature is the point match tolerance + the mt % (manufacturing tolerance). the mt % may be obtained from the r vs. t conversion tables and is added to the point match temperature, i.e., 1% tol. at 25? + 2.6% at -30? for curve 1 equals a total tolerance of 3.6% at -30?. a spreadsheet is available for the vishay thermistor materials that calculates beta, steinhart-hart equation constants a, b, and c, the resistance at any temperature based upon the steinhart constants or beta, the temperature equivalent of the resistance reading, and resistance temperature coefficients. this spread sheet will also calculate the total resistance tolerance of any point matched thermistor for temperatures in 10? increments, and the resistance tolerance at any temperature within the calibrated range of curve tracking thermistors. please contact factory if interested in this excel spreadsheet. point match tolerance computer aids for thermistor selection figure 2 point match tolerances vs. temperature resistance temperature 25 c nominal r vs. t max. r vs. t min. r vs. t pivot point (calibration temperature) ntc thermistors, coated
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