What are Temperature Sensors

What are Temperature Sensors

• The numerous kinds of temperature sensors are available in the market according to their use like a thermistor, resistance temperature detectors, etc.
• Every sensor has a different working principle like RTD measure temperature by variation in the resistance and thermocouple measure temperature by variation voltage at its terminals.

• As the working principle of every sensor is different but the common factor is that all these sensors calculate temperatures by detecting the alteration in the physical parameters of different substances like resistance, pressure and temperature.
• Each sensor after detecting physical parameters variation converts it into the temperature value and shows on the LCD connected with it.
• Temperature sensors are mostly used in high voltage (HV), alternating current (AC) networks, medical instruments, beverage system to maintain the temperature value for the safety of our different products.
• The thermometer is a frequently used temperature sensor, that computes the value of the temperature of fluids, solids substances, and different gaseous materials.
• I have shared a simulation in Labview for Temperature Sensing, which will help in better understanding.

  

Units of Temperature

• The most commonly used units for the temperature kelvin, Celsius and Fahrenheit.  Let's discuss them with the detailed.

• Celsius is mostly used temperature unit in the different engineering and industrial temperate measurements.
• It is an experimental scale that was formed by ancient development,  that defined its 0 points by comparing it to the freezing point of water and its hundred degrees compared with the point at which water boiled.

• This unit is used by metrologists for the measurement of the surface temperature. But mostly used temperature unit is Celsius so it can be easily converted into the Celsius by using this formula.

C = (F-32)/1.8

• This unit of temperature is used for the different scientific temperature measurements. It can also convert into the Celsius by this formula.

k=C +273

• If you are working on different temperature units and want to converts them easily you must try our temperature converters. That are listed here.
• Kelvin to Fahrenheit Converter
• Kelvin to Celsius Converter
• Fahrenheit to Kelvin Converter
• Fahrenheit to Celsius Converter
• Celsius to Rankine Converter
• Celsius to Kelvin Converter
• Celsius to Fahrenheit Converter
• Kelvin to Fahrenheit Converter
• Kelvin to Rankine Converter
• Rankine to Celsius Converter

Types of Temperature Sensors

• There are numerous categories of temperature sensors according to their working principle, applications and method of temperature measurement.
• We will discuss different and commonly used kinds of temperature sensors some important sensor are listed below. Let's discuss all these senors with the detailed.
  • Thermometer
  • Thermistor
  • Resistor temperature detectors (RTDs)
  • Semiconductor
  • Infrared Sensors

Thermocouples

• The thermocouple is the abbreviation of TC, it is generally used the sensor for temperature measurements.
• The physical structure of these sensors is very strong, less expensive, there is no need for separate power supply for this sensor, it has an internal battery.
• This module comprises of the 2 different metals that are recognised as open and closed. The working phenomena of the metals of the thermocouple follow the thermoelectric effect.
•  For the safety of thermocouple from different environments factors like temperature, moisture, pressure, and gases it is covered with plastic and different ceramic materials sheets.

• The general categories of the thermocouple are K, T, E, S, and B. The J, T, K are generally used thermocouples for temperature computations.

Resistor Temperature Detector

• The temperature's value calculates by the RTD has higher accuracy than other sensors.
• As with the variation of the resistance it measures the temperature, its resistance variation is directly proportional to the temperature values.
• The materials that are used for the construction of this sensor are Pt (platinum), nickel (ni) and copper (Cu).
• It can measure temperature form the minus two seventy celsius to eight fifty celsius.
• In this module, there is no internal power supply it needs external supply for continuous work.
• But the due current power loss occurs at the resistance that can be calculated by this formula.

?T = P x S

• In this equation, the T is temperature P is the power that loss at the resistance.

  

Thermistors

• A thermistor is a less costly, adjustable and can be used in easiest way. It measures the value of the temperature by the change in the resistance.
• Ther are 2 main types of the thermistors first one is NTC (negative coefficient thermistor) and second is PTC (positive temperature coefficient).
• In the case of the PTC, the temperature and the resistance is directly proportional to one another, with the increase of the temperature there is also an increment in the resistance.
• While in the  NTC the temperature and resistance are inversely proportional to each other.

• These sensors are formed by the oxides of the different metals like the manganese (Mn), nickel (ni).
• This sensor is highly sensitive it detects very minute variations in the temperature.

  

Thermometers

• To measure the temperature of the different matters like fluids, gaseous materials, and solids the thermometer is used.
• The word thermometer is a mixture of the 2 different words first one thermo that means heat and the second one is the meter that means to measure something.
• The thermometer is similar to a tube that is assembled by the glass and consists of the mercury.
• When the temperature rises the mercury in the tube expands according to the temperature and temperature value can be measured from the scaling on the wall of the tube.
• The value of the temperature can be measured in k (kelvin), F (Fahrenheit), centigrade (C) according to the set scale.

Semiconductor Sensors

• These sensors are available in the different integrated circuitries. Due to such type of designs, these are also recognised as the integrated circuit sensing devices.
•  There several types of these sensors like diode sensor, digital sensors, etc. The work at among the temperature range from fifty-five to plus one fifty celsius.
• The example of these senors are LM35 and AD590.

  

DS18B20 Temperature Sensor

• DS18B20 work on the single wire protocol and it used to measure temperature from  -55 Celsius to +125 Celsius. It can receive data from nine bit to twelve bits.
• As this sensor uses single wire protocol sensing and receiving data so it can very easily be controlled by the one pin of the microcontroller.
• A single wire is mostly used protocol and every DS18B20 consists of the sixty four-bit serial code that used to regulate more than one components by a single pin of the microcontroller.
• Due to the single wire protocol, the DS18B20 Arduino interfacing is very common to send and receive data and controlling of other senors.

  

IR (Infrared Radiation) Sensor

• This type of sensor used infrared radiations for the measurements of the temperature.
• There is no need for physical connection for these sensors with the device to that temperature has to find.
• For instance, if someone in the classroom and has an IR sensor than he can easily find the value of the temperature of the chair in the classroom.
•  There are 2 main categories of IR sensor first one is the quantum and the second one is thermal.