RTD and Thermocouple Assemblies: Comprehensive Temperature Sensing Solutions


RTD (Resistance Temperature Detector) and Thermocouple Sensors are available in a wide variety of calibrations, mounting configurations, materials, and sizes. They are designed for repeatability, accuracy, and stability over the life cycle of the instrumentation. Sensor assemblies can be specially designed for challenging applications using applied knowledge of thermodynamics, metallurgy, and electrical properties of materials.

RTD (Resistance Temperature Detector) Sensors

RTD sensors are crucial for precise temperature measurement and control in various industrial applications. They are known for their accuracy and stability over a wide temperature range. Available RTD sensors include:

  1. Thin Film RTDs: Suitable for general-purpose applications, offering fast response times and high stability.
  2. Wire-Wound RTDs: Ideal for applications requiring high accuracy over a broad temperature range, such as in the pharmaceutical and aerospace industries.
  3. Coiled Element RTDs: Designed for demanding environments where durability and long-term stability are essential.

Operating Principle of Thermocouples

When two dissimilar metal wires are joined together at one end, a voltage is produced at the other end that is approximately proportional to temperature. This phenomenon provides a simple way to electrically infer temperature: measure the voltage produced by the junction, and you can determine the temperature.

Thermocouples: This form of electrical temperature sensor is called a thermocouple. The junction of two different metals behaves like a temperature-sensitive battery. However, connecting any kind of electrical instrument to the thermocouple wires creates another junction of dissimilar metals, influencing the measurement.

Thermocouple Schematic Explanation

  • Junction J1: The junction between Iron (Fe) and Copper (Cu), which generates a voltage related to temperature.
  • Junction J2: Another junction between Iron (Fe) and Copper (Cu), but with an opposing polarity to J1. This junction is created when connecting the thermocouple wires to the voltmeter.
  • Junction J3: A junction between identical metals (e.g., Copper to Copper), which does not generate a temperature-dependent voltage.

How It Works:

  1. Junction J1 (Fe-Cu): This junction generates a voltage (V1) based on the temperature difference between the junction and the reference junction.
  2. Junction J2 (Fe-Cu): This second junction generates a voltage (V2) of opposite polarity to J1.
  3. Junction J3 (Cu-Cu): This junction does not affect the voltage measurement as it is between identical metals.

When the entire system is at the same temperature, the voltages generated by J1 and J2 are equal in magnitude but opposite in polarity, resulting in a net voltage of zero (V1 – V2 = 0). However, when J1 and J2 are at different temperatures, the voltmeter registers a voltage corresponding to the temperature difference between the two junctions.

Key Points:

  • The voltmeter measures the net voltage difference between the two junctions (J1 and J2).
  • Accurate temperature measurement relies on having a known reference temperature or using a reference junction compensation technique.

When both J1 and J2 are at the same temperature, the voltmeter reads 0 volts. Only when J1 and J2 are at different temperatures will the voltmeter register a voltage.

Vacuum Rated Thermocouples

One of the biggest challenges facing the vacuum industry is to collect multiple readings from complex assemblies while being limited by the number of existing feedthrough ports in a vacuum chamber. The Multi-TC, Flanged Feedthrough solves this by embedding multiple thermocouples in one feedthrough, customizable to meet specific application requirements.

Features of the Multi-TC, Flanged Feedthrough

  • Replaceable thermocouple(s) design
  • Vacuum Integrity: 10-8 atm.cc/sec
  • Multiple types and lengths available for thermocouple(s)
  • Multiple types and sizes available for flange(s)
  • Multiple types and sizes available for lead wires (KAPTON available for minimal contaminant release)
  • Compatible O-rings available for flange(s)
  • Adaptable to virtually any temperature range


  • Single or multipoint sensor assemblies
  • NIST traceable calibration on refractory thermocouple materials
  • 100, 1000, and 2000 Ohm RTD assemblies
  • Stock & standard designs for quick delivery
  • Teflon coated probe capability

High Temperature Piezoelectric Force Sensors

In addition to temperature sensors, high temperature piezoelectric force sensors are available for applications that require precise force measurement under extreme conditions. These sensors are designed to maintain accuracy and stability at high temperatures, making them ideal for aerospace, automotive, and industrial applications.

Temperature Sensor Calibration

Accurate temperature measurement depends on proper sensor calibration. Both RTD and thermocouple sensors can be calibrated to ensure precision and reliability in various environments. NIST traceable calibration is available for refractory thermocouple materials, ensuring the highest standards of accuracy.

Temperature Detector Sensors and Sensing

Temperature detector sensors are essential for monitoring and controlling temperatures in industrial processes. With advanced temperature sensing technology, these sensors provide reliable data to maintain optimal operating conditions.

Engineering & Quality Assurance

Engineers provide decades of experience in design and development, delivering a wealth of empirical data and experience. Custom requirements are welcome, with parts designed to meet challenging needs. Recognized for commitment to quality and excellence, certified in accordance with ISO 9001:2015.

Related Post

Shopping Cart
Scroll to Top
Scroll to Top