Honeywell Sensing and Control

Resistance-Temperature Conversion Table No. 17
R-T Tables Index  R-T Tables Index

Multiply resistance of thermistor at 25 °C by appropriate horizontal row value in line with the specified temperature to obtain resistance.

Conversion Specifications
Parameter Value
R-T Curve No. 17
Material TYPE C
Type Units UNICURVES & CHIPS
*Ro Ranges
(OHM)
For Discs
TYPE   DIA.
140 .1 in
143 .2 in
150 .3 in
153 .4 in
For Chips
Type
190-199
UNICURVES
TYPE   Ro
192 300
194 300
196 100-300

CHIPS
TYPE Ro
175 1 k-3 k
195,196 100-300
197 100-300
198 100-300
199 100-300
Curve Material XXX-XXX C XX-XXX
β 0/50 °C 3100 ± 175
Ratio Ro @ 0/50 °C 5.80
Ratio Ro @ 25/125 °C 14.25
Temp. Coef. (α) @ 25 °C -3.5 %/°C
R-T Conversion
°F °C R-T Curve Coefficient Alpha Temp. Coefficient Resistance Deviation
-76 -60 51.75 6 9.7
-58 -50 28.63 5.6 8.2
-40 -40 16.51 5.2 6.8
-22 -30 9.881 4.9 5.5
-4 -20 6.117 4.5 4.4
14 -10 3.906 4.3 3.3
32 0 2.565 4 2.3
50 10 1.729 3.8 1.3
68 20 1.194 3.6 0.3
77 25 1 3.5 0
86 30 0.8422 3.4 0.6
104 40 0.6063 3.2 1.4
122 50 0.4446 3.1 2.4
140 60 0.3317 2.9 3.1
158 70 0.2514 2.8 3.7
176 80 0.1932 2.7 4.4
194 90 0.1472 2.6 5.1
212 100 0.119 2.5 5.7
230 110 - - -
248 120 - - -
257 125 - - -
266 130 - - -
284 140 - - -
302 150 - - -
320 160 - - -
356 180 - - -
392 200 - - -
428 220 - - -
464 240 - - -
500 260 - - -
538 280 - - -
572 300 - - -

*Ro - Resistance at 25 °C, zero power applied.

ALPHA TEMPERATURE COEFFICIENT - The Alpha temperature coefficient denotes the percent in resistance change per °C at a specific temperature.

RESISTANCE-DEVIATION - The Ro deviation must be added to the resistance tolerance at the reference temperature to give the complete percentage of resistance deviation. This reference point for standard catalog thermistors is 25 °C. As an example: at 25 °C, a thermistor is selected having 10 % resistance tolerance with R-T characteristics per curve 4 (Type N). The total resistance deviation from a normal R-T curve will therefore be 10 % at 25 °C plus 2.5 at 0 °C and will have a total deviation of 12.5 % maximum at 0 °C.