A Temperature Transducer is a device that converts the thermal quantity into any physical quantity such as mechanical energy, pressure and electrical signals etc. Published By: Arslan Farooq UOL'18

1. Instrumentation and
Measurements
Arslan Farooq
Presentation Topic :- Thermocouple as a Transducer
Dept. of Mechanical Engineering
The University of Lahore

2. Outline
 Introduction
 Principle
 Description
 Types
 Applications
 Advantages
 Disadvantages

3. Transducers:-
Transducers are used in instrumentation systems to
interface physical quantities with analytical ones.

4. Thermocouple:-
 A thermoelectric transducer that converts
heat directly into electricity, according to the
Seebeck effect.
 This can be used to generate electricity,
measure temperature difference or change
the temperature of objects.

5. The Seebeck Effect
Eemf = - S T where, S is the Seebeck coefficient.

6. Description
Its construction consists of two conductors, welded
together at the measuring point and insulated from
each other along the length, inside an outer protection
sheath.

7. TYPES OF THERMOCOUPLES
There are many thermocouples but 8 of them are
internationally standardized.
Base Metal involves:-
 Type K : Chromel-Alumel
 Type J : Iron-Constantan
 Type T : Copper-Constantan
 Type E : Chromel-Constantan
 Type N : Nicros-Nisil

8. TYPES OF THERMOCOUPLES Cont.
Noble Metals Includes:-
 Type S : Platinum-Rhodium
 Type B : Platinum-Rhodium
 Type R : Platinum-Rhodium
Each thermocouple type has a specific range of temperature
and environment.

9. APPLICATIONS
 Temperature Measurement
 Power Generation
 Radiation Sensors
 Gas Safety Equipments
 Manufacturing Industry Thermocouples

10. ADVANTAGES
 Rugged
 Inexpensive
 Quick response time
 Very simple in construction
 Used to measure temperature ranging around -200 C to
2200 C

11. DISADVANTAGES
 Low accuracy
 Vulnerable to corrosion
 Thermocouple operation is relatively complex
with potential sources of error

12. ANY QUESTIONS?