Temperature Sensor – Types of Sensor

Temperature sensor: 
Temperature sensor is a device, used to measure the temperature using an electrical signal. It requires a thermocouple or RTD(Resistance temperature Detector). It is the most common and most popular sensor.
Temperature sensor, the change in the temperature correspond to change in its physical property like resistance or voltage.

TEMPERATURE SENSOR

Working :
The measurement of the temperature sensor is about the coolness or hotness of an entity.
The working of the sensor is the voltage that read across to the diode. If increment in voltage, then the temperature increases and there is a voltage decrement between the transistors terminals of emitter & base. That data saved by the sensor.

If the difference in voltage is amplified, then analog signal is generated by the device, and it is directly proportional to the temperature.

Types of temperature sensor :

• Thermocouple sensor
• Thermistor sensor
• Resistance temperature detector
• Thermometer
• IR temperature sensor
• Semiconductor based sensor

1. Thermocouple sensor –
   A thermocouple sensor is a temperature measuring tool lies two different conductors that contact each other at one or more points. It produces a voltage when the temperature of one of the points differs from the reference temperature of one of the points differs from the reference temperature at other parts of the circuits.
2. Thermistor sensor –
   This type of sensors is widely used in the human thermometers. If there are changes in the temperatures, then the electric current or resistance also change. 
   The thermistor is made by using the semiconductor materials with a resistivity which is especially sensitive to temperature.
   The resistance of a thermistor decreases with increasing temperature so that when the temperature changes, the resistance changes predictable.
3. Resistance temperature detector –
   They are the temperature sensors. Temperature sensors with a resistor what changes the resistive value cumulatively temperature changes. 
   Resistance temperature detector(RTD) are used in a wide temperatures range from -500c to 5000c for thin film and for the wire wound variety the range is from the +2000c to 8500c. A thin layer of platinum on an underlying substance is present on the thin film (Resistance temperature detector) element. A new type of model is created who provide the electrical circuit, and it is well-ordered to provide specific resistance.
4. Thermometer –
   It is a device which is used to measure the temperature of any class solid or liquid in this type of alcohol is used in a tube whose volume is changed by changing the temperature.
   Its volume is directly proportional to temperature.
5. IR temperature sensor –
   These are an electronic and non contacting sensors which have a certain characteristic such that it can EMIT the IR radiations. Two types of IR temperature sensor used in market are IR sensor and Quantum IR sensor the surface temperature by emitting radiation does its cost depend on its working its  accuracy level depend upon  its cost in other words low cost- low accuracy level and high cost -high accuracy level.
6. Semiconductor based sensor –
   It operates with the reverse bias has a small capacitance and low leakage current. They are formed on thin wafers of silicon. They are compact, produce linear output and have a small range of temperature. They also have low-cost and accurate following calibration. 

          Types of Semiconductor based sensor –

• Voltage output
• Current output
• Digital output
• Resistance output
• Simple diodes

Applications of Temperature sensor :

• These are used in electric motors for measuring the motor winding temperature, bearing temperature, brushes temperature.
• These are used in electric cables for measuring the table internal temperature.
• In mechanical engine for measuring engine oil temperature engine bearing temperature.
• In rubber, plastic, biomedical industries.