Temperature is the most commonly measured physical parameter. Whether we talk about process industry or are it a laboratory. So exact measurement is needed many in applications such as medical research lab electrical and electronics components. So temperature sensor are used to measure temperature makes circuits which control various types of equipment temperature is a physical quantity which measure the degree of hotness or coldness of an object or substance measured on a definite scale such as Fahrenheit, Celsius etc. A temperature sensor is an electronic device that measures temperature and convert it into signal to record.
Different types of temperature sensor
Contact and non-contact temperature sensor
Temperature sensor like thermometer requires direct contact with the physical object that is being monitored are called contact temperature sensor. Contact temperature sensor are those switched require contact with physical object that is being monitored under this comes thermistor, thermocouple, thermometer, RTD that is resistance temperature detector, semiconductor sensors etc. and Temperature sensor are those that indirectly measure temperature of an object are called non-contact temperature sensor for example IR sensor.
Thermometer
- Thermometer it is very basic type of temperature sensor. The name thermometer is a combination of two words: thermo means heat, and meter means to measure
- A thermometer is a device used to measure the temperature of solids, liquid and gases.
- Thermometer contains a liquid which is mercury or alcohol in its glass tube. When the liquid is heated it expands inside the narrow tube of the thermometer. It has a calibrated scale to indicate the temperature.
- Temperature can be recorded in these scales has Fahrenheit, Celsius or Kelvin.
Thermocouple
- Thermometer sensor is the most commonly used temperature sensor it is abbreviated as TC.
- It is made by joining two dissimilar metals at one end. The joined end is referred to as the HOT JUNCTION. The other end of these dissimilar metals is referred to as the COLD JUNCTION.
- The cold junction is formed at the last point of TC material.
- If there is a difference in temperature between the hot junction and cold junction, small voltage is created. This voltage is referred to as an EMF (electromotive force).
- Thermocouple are classified into different types namely type-K, type-J, type-T, type-E, type-N, type-S, type-R and type-B.
Thermistor
- A type of resistor whose resistance value is sensitive to the range in temperature is known as thermistor.
- The principle obeyed by the thermistor is its dependency on-resistance value on the change in temperature.
- The change in the resistance is depending upon the material chosen in the construction of the thermistor.
- The thermistors are made by using ceramic or polymers. They are of two types NTC and PTC.
- NTC is negative temperature coefficient that means resistance decrease with increase in temperature and PTC that is positive temperature coefficient that means resistance increase with increasing in temperature.
Resistance temperature detector (RTD)
- RTD sensor is one of the most accurate sensors. In an RTD, the resistance is proportional to the temperature.
- This sensor is made from metals like platinum, nickel, copper etc.
- It has a wide range of temperature measurement capabilities as it can be used to measure temperature in the range between -2700C to +8500C.
- There are different types of techniques to measure temperature by using this RTD. They are two wired, three-wired and four-wired method.
- RTD requires an external current source to function properly.
Semiconductor sensor
- Semiconductor sensors are the devices that come in the form of ICs. Popularly, these are known as an IC temperature sensor.
They are classified into different types
- Current output temperature sensor
- Voltage output temperature sensor
- Resistance output silicon temperature sensor
- Diode temperature sensor
- Digital output temperature sensor
- Present semiconductor temperature sensors offer high linearity and high accuracy over an operating range of about 55 0C to +150 0
Infrared radiation (IR)
- Infrared radiation a type of electromagnetic radiation in visible range spectral range of red and longer wavelength of microwave radiation and its frequency lies between that of 300 GHz to 430 THz.
- IR sensor is an electronic instrument which is used to sense certain characteristics of its surrounding by either emitting or detecting IR radiation.
- These sensors are non-contacting sensors for example, if you hold an IR sensor in front of any object without establishing any contact, the sensor detects the temperature of the object based on the merits of its radiation.
- These sensors are classified into two types such as thermal infrared sensors and quantum infrared sensors.
Applications of Sensor
- They are used in electric motors for measuring the motor winding temperature, internal housing temperature, bearing temperature, brushes temperature and external body temperature.
- These are used in HVAC (heating ventilation and air conditioning) system for controlling the temperature of shopping malls building, university building, hospital building and industrial and commercial
- These are frequently used in humidity and air control conditioning equipment.
- These are used in electric cables for measuring the cables internal temperature and in this application; these are used in the form of heat shrink tube or metal housing.
- These sensors are frequently used in water incoming tubes for measuring the water internal temperature.
- These sensors have so many applications in renewable energy applications such as in solar heating pumps, biomass combustion applications wind power applications, geothermal drilling applications and in rail vehicles.
- These sensors are used in rubber and plastic industry.
- These sensors also have so many applications in biomedical industry.
Advantages of temperature sensor
- By using these sensors, the motor temperature could be controlled easily and motor could be on or off automatically and save the motor.
- By using these sensors, the electric cables could be saved from burning due to overheating.
- By using these sensors, the user could easily control the engine oil and bearing temperature.
- By using these sensors, the user can easily control the room temperature automatically by switching on or off the cooling system
- By using these sensors, the user can easily control the humidity and air conditioning of their buildings.
- By using these sensors, the user can easily check the water temperature and switch on or off the water heater and control the monthly bill.
- By using these sensors, the drilling operate could easily control the drilling temperature in geothermal application.
Temperature is the most commonly measured physical parameter. Whether we talk about process industry or are it a laboratory. So exact measurement is needed many in applications such as medical research lab electrical and electronics components. So temperature sensor are used to measure temperature makes circuits which control various types of equipment temperature is a physical quantity which measure the degree of hotness or coldness of an object or substance measured on a definite scale such as Fahrenheit, Celsius etc. A temperature sensor is an electronic device that measures temperature and convert it into signal to record.
Different types of temperature sensor
Contact and non-contact temperature sensor
Temperature sensor like thermometer requires direct contact with the physical object that is being monitored are called contact temperature sensor. Contact temperature sensor are those switched require contact with physical object that is being monitored under this comes thermistor, thermocouple, thermometer, RTD that is resistance temperature detector, semiconductor sensors etc. and Temperature sensor are those that indirectly measure temperature of an object are called non-contact temperature sensor for example IR sensor.
Thermometer
- Thermometer it is very basic type of temperature sensor. The name thermometer is a combination of two words: thermo means heat, and meter means to measure
- A thermometer is a device used to measure the temperature of solids, liquid and gases.
- Thermometer contains a liquid which is mercury or alcohol in its glass tube. When the liquid is heated it expands inside the narrow tube of the thermometer. It has a calibrated scale to indicate the temperature.
- Temperature can be recorded in these scales has Fahrenheit, Celsius or Kelvin.
Thermocouple
- Thermometer sensor is the most commonly used temperature sensor it is abbreviated as TC.
- It is made by joining two dissimilar metals at one end. The joined end is referred to as the HOT JUNCTION. The other end of these dissimilar metals is referred to as the COLD JUNCTION.
- The cold junction is formed at the last point of TC material.
- If there is a difference in temperature between the hot junction and cold junction, small voltage is created. This voltage is referred to as an EMF (electromotive force).
- Thermocouple are classified into different types namely type-K, type-J, type-T, type-E, type-N, type-S, type-R and type-B.
Thermistor
- A type of resistor whose resistance value is sensitive to the range in temperature is known as thermistor.
- The principle obeyed by the thermistor is its dependency on-resistance value on the change in temperature.
- The change in the resistance is depending upon the material chosen in the construction of the thermistor.
- The thermistors are made by using ceramic or polymers. They are of two types NTC and PTC.
- NTC is negative temperature coefficient that means resistance decrease with increase in temperature and PTC that is positive temperature coefficient that means resistance increase with increasing in temperature.
Resistance temperature detector (RTD)
- RTD sensor is one of the most accurate sensors. In an RTD, the resistance is proportional to the temperature.
- This sensor is made from metals like platinum, nickel, copper etc.
- It has a wide range of temperature measurement capabilities as it can be used to measure temperature in the range between -2700C to +8500C.
- There are different types of techniques to measure temperature by using this RTD. They are two wired, three-wired and four-wired method.
- RTD requires an external current source to function properly.
Semiconductor sensor:- - Semiconductor sensors are the devices that come in the form of ICs. Popularly, these are known as an IC temperature sensor.
They are classified into different types
- Current output temperature sensor
- Voltage output temperature sensor
- Resistance output silicon temperature sensor
- Diode temperature sensor
- Digital output temperature sensor
- Present semiconductor temperature sensors offer high linearity and high accuracy over an operating range of about 55 0C to +150 0
Infrared radiation (IR)
- Infrared radiation a type of electromagnetic radiation in visible range spectral range of red and longer wavelength of microwave radiation and its frequency lies between that of 300 GHz to 430 THz.
- IR sensor is an electronic instrument which is used to sense certain characteristics of its surrounding by either emitting or detecting IR radiation.
- These sensors are non-contacting sensors for example, if you hold an IR sensor in front of any object without establishing any contact, the sensor detects the temperature of the object based on the merits of its radiation.
- These sensors are classified into two types such as thermal infrared sensors and quantum infrared sensors.
Applications of Sensor
- They are used in electric motors for measuring the motor winding temperature, internal housing temperature, bearing temperature, brushes temperature and external body temperature.
- These are used in HVAC (heating ventilation and air conditioning) system for controlling the temperature of shopping malls building, university building, hospital building and industrial and commercial
- These are frequently used in humidity and air control conditioning equipment.
- These are used in electric cables for measuring the cables internal temperature and in this application; these are used in the form of heat shrink tube or metal housing.
- These sensors are frequently used in water incoming tubes for measuring the water internal temperature.
- These sensors have so many applications in renewable energy applications such as in solar heating pumps, biomass combustion applications wind power applications, geothermal drilling applications and in rail vehicles.
- These sensors are used in rubber and plastic industry.
- These sensors also have so many applications in biomedical industry.
Advantages of temperature sensor
- By using these sensors, the motor temperature could be controlled easily and motor could be on or off automatically and save the motor.
- By using these sensors, the electric cables could be saved from burning due to overheating.
- By using these sensors, the user could easily control the engine oil and bearing temperature.
- By using these sensors, the user can easily control the room temperature automatically by switching on or off the cooling system
- By using these sensors, the user can easily control the humidity and air conditioning of their buildings.
- By using these sensors, the user can easily check the water temperature and switch on or off the water heater and control the monthly bill.
- By using these sensors, the drilling operate could easily control the drilling temperature in geothermal application.
