This document discusses thermistors, which are temperature sensing elements that measure temperature through changes in resistance. It describes how thermistors are constructed from sintered semiconductor materials and come in various shapes. The document outlines the working principle of thermistors, types including positive and negative temperature coefficient thermistors, advantages like low cost and high sensitivity, disadvantages such as non-linear output, and applications including current limiting devices, digital thermostats, and battery pack monitors.

1. Thermistor
Department of Chemical Engineering
Submitted by:-
Krishna Kant Nayak
Student MNIT Jaipur

2. Index
1. Introduction
2. Construction
3. Working
4. Types
5. Advantages
6. Disadvantages
7. Applications
8. References

3. THERMISTOR
 A temperature sensing element which measures temperature according
to change in resistance.
 It is usually made of a sintered semiconductor material.
 They can or cannot be self heated.
 They use ceramic or polymer materials while RTDs use pure metals.
 They are available in various shapes like disc, rod, washer, etc.

5. CONSTRUCTION

6. WORKING
 1/T=A+B*ln(R)+C∗(ln(R))
𝟑
 ∆𝑹 = 𝒌∆𝑻
 𝑹 𝟏 = 𝑹 𝟐 𝒆𝒙𝒑
𝜷
𝟏
𝑻 𝟏
−
𝟏
𝑻 𝟐

7. TYPES
 Positive Temperature Coefficient
Thermistor
 Negative Temperature
Coefficient Thermistor

8. ADVANTAGES
 Low cost.
 Sensitivity is high.
 Small in size.
 Good stability.
 High output signal.
 Easy to transport.

9. DISADVANTAGES
 Non-linear output is seen.
 Not suitable for high temperature measurement.
 Requires external power supply.
 Shielded cables should be used to minimize interference.
 Self-heating.

10. APPLICATIONS
1. PTC Thermistor
i. Current limiting devices.
ii. Timer in degaussing coil
iii. Motors
iv. Self regulating heaters
2. NTC Thermistor
i. Very low temperature thermometers
ii. Digital thermostats
iii. In-rush protection devices
iv. Battery pack monitors

11. REFERENCES
 https://www.teamwavelength.com/info/thermistors.php
 https://en.wikipedia.org/wiki/Thermistor
 http://www.resistorguide.com/thermistor/
 http://www.electronicshub.org/thermistors-types-and-
applications/
 https://www.elprocus.com/introduction-to-thermistor-
types-with-its-workings-and-applications/