Join 60,000+ competitive exam aspirants
or with email
Your Cart
Subtotal₹0
Total₹0
Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
Join 60,000+ competitive exam aspirants
Thermocouples are generally used for accurate temperature measurement upto
100°C
250°C
500°C
1600°C
1600°C
Quick Summary: Thermocouples are thermoelectric sensors capable of measuring temperatures over a very wide range, typically extending up to 1600°C or higher depending on the materials used (e.g., Type R, S, or B thermocouples). They are the primary choice for high-temperature industrial applications where robust and wide-range sensing is required.
Thermocouples are thermoelectric sensors capable of measuring temperatures over a very wide range, typically extending up to 1600°C or higher depending on the materials used (e.g., Type R, S, or B thermocouples). They are the primary choice for high-temperature industrial applications where robust and wide-range sensing is required.
E=αΔT — Linear approximation of Seebeck EMF
V=∫TrefThot(SA−SB)dT — Exact integral form
A thermocouple works on the Seebeck effect, where two dissimilar metal wires joined at one end produce a small voltage proportional to the temperature difference between the junction (hot junction) and the reference end (cold junction). The magnitude of the generated EMF is given by E=∫T1T2(αA−αB)dT, where α represents the Seebeck coefficients of the two metals.
Thermocouples consist of two dissimilar metal conductors forming a junction.
Type K is common up to 1260°C; Type S/R/B are used for temperatures up to 1600°C+.
They are self-powered and do not require external excitation.
The output signal is in the millivolt range, requiring amplification.
Extremely wide temperature range
Fast response time
Rugged and inexpensive
High repeatability
Low accuracy compared to RTDs
Requires cold junction compensation
Non-linear output characteristics
Industrial furnace monitoring
Gas turbine exhaust measurement
HVAC temperature sensing
Manufacturing processes
Type B thermocouples specifically can handle temperatures up to 1800°C for short periods.
Option A (100°C) and B (250°C) are well within the operating range of even the simplest thermocouples, making them incorrect as the upper limit.
D is correct — Thermocouples are industrially utilized for high-temperature sensing, with specialized types (like Noble Metal thermocouples) capable of accurate measurement up to 1600°C.
Always remember that RTDs are generally more accurate for low-to-medium temperatures, while Thermocouples are preferred for high-temperature and harsh industrial environments.