Temperature Measurement using Thermostatic temperature, Resistance Temperature Detectors(RTD), Thermistors, and Thermocouples — Lesson 3

This lesson covers the principles of temperature measurement using thermocouples and thermistors, two types of resistance temperature detectors (RTDs). It delves into the operational mechanisms of these devices, explaining how they exploit changes in resistance with temperature to measure temperature. The lesson also discusses the Seeback, Peltier, and Thompson effects, which are crucial to understanding the functioning of thermocouples. It further explains how a thermometer can be created by calibrating the output voltage across the non-junction ends of the wire. The lesson concludes with a discussion on the laws of intermediate metals and intermediate temperatures, which are used to construct thermocouple circuits.

Video Highlights

02:35 - Use of RTDs in different environments and how the change in resistance of the material is used to measure temperature
05:31 - How the resistance of a thermistor is given as a function of absolute temperature
10:24 - Discussion on the sensitivity of thermistors
16:12 - Construction and working principle of thermocouples
22:15 - Seeback effect, Peltier effect, and Thompson effect
34:17 - Laws of intermediate metals and intermediate temperatures used in constructing thermocouple circuits

Key Takeaways

- Thermocouples and thermistors are types of resistance temperature detectors (RTDs) that measure temperature by exploiting changes in resistance with temperature.
- The Seeback, Peltier, and Thompson effects are crucial to understanding the functioning of thermocouples.
- A thermometer can be created by calibrating the output voltage across the non-junction ends of the wire, provided the current is very small and the thermal environment of each conductor is the same.
- The laws of intermediate metals and intermediate temperatures are used to construct thermocouple circuits.