Thermal resistance is the most commonly used temperature detector in the middle and low temperature areas.

Wire-connection mode

Thermal resistance temperature measurement is based on the characteristic that the resistance value of a metal conductor increases with the increase in temperature for temperature measurement.

Its main features are high measurement accuracy and stable performance. Among them, platinum thermal resistance has the highest measurement accuracy. It is not only widely used in industrial temperature measurement, but also made into a standard reference instrument. They are mostly made of pure metal materials. At present, platinum and copper are the most widely used. In addition, materials such as nickel, manganese and rhodium have been used to make thermal resistors. There are many types of temperature-sensing materials commonly used for metal thermal resistance, and the most commonly used is platinum wire. In addition to platinum wire, metal thermal resistance materials for industrial measurement include copper, nickel, iron, iron-nickel, etc.

Sino-Inst offers a variety of thermal resistance for industrial level measurement. If you have any questions, please contact our sales engineers.

What is the formula of thermal resistance?

  • The temperature measurement principle of the thermal resistance is different from the temperature measurement principle of the thermocouple in that the thermal resistance is based on the thermal effect of the resistance for temperature measurement, that is, the resistance of the resistor changes with the temperature. Therefore, as long as the resistance change of the thermal resistance is measured, the temperature can be measured. At present, there are mainly two types of metal thermal resistance and semiconductor thermistor.The resistance value and temperature of a metal thermal resistance can generally be expressed by the following approximate relationship, namely
  • Rt=Rt0[1+α(t-t0)]
  • In the formula, Rt is the resistance value at temperature t; Rt0 is the corresponding resistance value at temperature t0 (usually t0=0°C); α is the temperature coefficient.The relationship between the resistance and temperature of the semiconductor thermistor is
  • Rt=AeB/t
  • In the formula, Rt is the resistance value when the temperature is t; A and B depend on the constant of the structure of the semiconductor material.


It is usually used along with display instruments, recording instruments, electronic computers and so on. It is able to directly measure the temperature of liquid, steam and gas and solid surface within the range of -200℃~500℃.

Working Principle

Thermal resistance uses the feature that when the temperature of the material changes, its resistance will change too. When the resistance changes, the instrument will display relevant temperature corresponding to the resistance.


  • With temperature-sensing element of pressure spring type, so it has good anti-vibration performance;
  • With no compensation wire, which is cost-saving;
  • High measurement accuracy;
  • High mechanical strength, good pressure resistance;
  • Imported thin-film resistor with reliable and stable performance;

Read more about Thermal resistance

Main Technical Parameters

Product implementation standard:IEC60751,GB/T30121-2013,JB/T 8623-1997.

Temperature Range And Tolerance Level

GraduationTolerance levelWire wound element effective temperaturerangeMembrane element effective temperaturerangeRange of temperature measurement
Pt100AA-50~2500~150±(0.1+0.0017丨t丨 )
Pt100A-100~450-30~300±(0.15+0.002丨t丨 )
Pt100B-196~600-50~500±(0.3+0.005丨t丨 )
Pt100C-196~600-50~600±(0.6+0.01丨t丨 )
Pt100-50~150±(0.3+0.006丨t丨 )
t = temperature Absolute value,units for C

product Description

Thermal Resistance With No-fixed Device

Thermal resistance with no-fixed device  1

WZP-120 WZP -120 2 WZP-120G WZP -120G 2 WZP-121 WZP -121 2 WZP- 121G WZP -121G 2 WZP- 130 WZP -130 2 WZP- 130G WZP -130G 2 WZP- 131 WZP -131 2 WZP- 131G WZP -131G 2 WZC-120G WZC-120 WZC-130 WZC-130G WZC-121 WZC-121G WZC-131 WZC-131G

1) Model 120 and 121 are anti-spring type with the protective grade being IP65; Model 130 and 131 are waterproof type with the protective grade grade being IP55. 2) Protective tube material is 1Cr18Ni9Ti and the rest of the material is ordered according to the agreement.

Fixed Screw Type Thermal Resistance

Fixed screw type thermal resistance  1

WZP-220 WZP -220 2 WZP-220G WZP -220G 2 WZP-221 WZP -221 2 WZP- 221G WZP -221G 2 WZP- 230 WZP -230 2 WZP- 230G WZP -230G 2 WZP- 231 WZP -231 2 WZP- 231G WZP -231G 2 WZC-220 WZC-220G WZC-230 WZC-230G WZC-221 WZC-221G WZC-231 WZC-231G

1) Model 220 and 221 are anti-spraying type with the waterproof grade being IP65. model 230 and 231 are waterproof type with the protective grade being IP55. 2) Protective tube material is 1Cr18Ni9Ti and the rest of the material is ordered according to the agreement. 3) Nominal pressure is ≤4.0MPa.

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