Thermistors are resistors whose resistance changes with temperature. They are commonly used for temperature sensing applications and can be classified as Positive Temperature Coefficient (PTC) or Negative Temperature Coefficient (NTC). PTC thermistors have increasing resistance with higher temperatures and are used for overcurrent protection and self-regulating heating. NTC thermistors have decreasing resistance with higher temperatures and are used for temperature sensing. Thermistors are made from metal oxides and work by changing resistance based on temperature-dependent changes in charge carriers in the material.

2. INTRODUCTION
INTRODUCTION
Thermistor is a type of resistor whose
resistance changes with temperature. It is
commonly used in temperature sensing
applications. Thermistors can be classified into
two types: Positive Temperature Coefficient (PTC)
and Negative Temperature Coefficient (NTC).
Thermistor is a type of resistor whose
resistance changes with temperature. It is
commonly used in temperature sensing
applications. Thermistors can be classified into
two types: Positive Temperature Coefficient (PTC)
and Negative Temperature Coefficient (NTC).

3. PTC thermistors are thermistors whose
resistance increases with increasing
temperature. They are commonly used as
overcurrent protectors and self-regulating
heating elements. PTC thermistors have a
non-linear resistance-temperature
characteristic.
PTC thermistors are thermistors whose
resistance increases with increasing
temperature. They are commonly used as
overcurrent protectors and self-regulating
heating elements. PTC thermistors have a
non-linear resistance-temperature
characteristic.
PTC THERMISTORS
PTC THERMISTORS

4. NTC thermistors are thermistors whose
resistance decreases with increasing
temperature. They are commonly used in
temperature sensing applications. NTC
thermistors have a negative temperature
coefficient of resistance and a non-linear
resistance-temperature characteristic.
NTC thermistors are thermistors whose
resistance decreases with increasing
temperature. They are commonly used in
temperature sensing applications. NTC
thermistors have a negative temperature
coefficient of resistance and a non-linear
resistance-temperature characteristic.
NTC THERMISTORS
NTC THERMISTORS

5. A thermistor is made of oxides of metals
such as Nickel, Manganese, Cobalt, Copper,
Uranium etc. These oxides are blended in a
suitable proportion and compressed into the
desired shapes from the mixed powers and
heat treated to recrystallise them, resulting
in a dense ceramic body with the required
resistance temperature characteristics. It is
available in a variety of shapes and sizes.
Commonly used for configurations are Disk
type, Bead type and Rod type.
A thermistor is made of oxides of metals
such as Nickel, Manganese, Cobalt, Copper,
Uranium etc. These oxides are blended in a
suitable proportion and compressed into the
desired shapes from the mixed powers and
heat treated to recrystallise them, resulting
in a dense ceramic body with the required
resistance temperature characteristics. It is
available in a variety of shapes and sizes.
Commonly used for configurations are Disk
type, Bead type and Rod type.
CONSTRUCTION OF
THERMISTOR
CONSTRUCTION OF
THERMISTOR

6. HOW THERMISTORS WORK
HOW THERMISTORS WORK
Thermistors work by utilizing the
temperature dependence of the
semiconductor material from which they are
made. As the temperature changes, the
number of charge carriers in the material
changes, which in turn changes the
resistance of the thermistor. The relationship
between resistance and temperature is non-
linear.
Thermistors work by utilizing the
temperature dependence of the
semiconductor material from which they are
made. As the temperature changes, the
number of charge carriers in the material
changes, which in turn changes the
resistance of the thermistor. The relationship
between resistance and temperature is non-
linear.

7. Relation between the temperature
and the resistance
Relation between the temperature
and the resistance
• The relation between the temperature and the resistance of
the thermistor is mathematically expressed by the equation
:RT₁ = RT₂ exp[β((1/T₁)-(1/T₂) ]
Where,
RT₁ - Resistance of the thermistor at temperature T₁ in Kelvin.
RT₂ - Resistance of the thermistor at temperature T₂ in Kelvin.
β-temperature depending on the material of thermistor.
• The relation between the temperature and the resistance of
the thermistor is mathematically expressed by the equation
:RT₁ = RT₂ exp[β((1/T₁)-(1/T₂) ]
Where,
RT₁ - Resistance of the thermistor at temperature T₁ in Kelvin.
RT₂ - Resistance of the thermistor at temperature T₂ in Kelvin.
β-temperature depending on the material of thermistor.

8. Applications of Thermistor
Applications of Thermistor
The main function of a thermistor is to be used as a temperature sensor.
They are used in digital thermometers.
Thermistors are used to control and maintain the temperature of a room for
domestic and office use.
They are used in automobiles to monitor the temperature.
They are used for protection against overcurrent in electrical circuits and also
act as a fuse.
The Inrush thermistors are used for the safe starting of electrical motor.
They also provide time delays in an electrical circuits.
The main function of a thermistor is to be used as a temperature sensor.
They are used in digital thermometers.
Thermistors are used to control and maintain the temperature of a room for
domestic and office use.
They are used in automobiles to monitor the temperature.
They are used for protection against overcurrent in electrical circuits and also
act as a fuse.
The Inrush thermistors are used for the safe starting of electrical motor.
They also provide time delays in an electrical circuits.

9. CONCLUSION
CONCLUSION
Thermistors are versatile and useful components in electronic circuits.
They can be used for temperature sensing, overcurrent protection, self-
regulating heating elements, and temperature compensation. PTC and
NTC thermistors have different characteristics and are used for different
applications.
Thermistors are versatile and useful components in electronic circuits.
They can be used for temperature sensing, overcurrent protection, self-
regulating heating elements, and temperature compensation. PTC and
NTC thermistors have different characteristics and are used for different
applications.

10. THANK YOU
THANK YOU
Do you have any questions?
Do you have any questions?