How the temperature sensor works

Temperature sensors use various principles to measure temperature and convert it into electrical signals. How they work includes: Thermocouples utilize the thermal electromotive force between dissimilar metals; RTDs measure resistance as a function of temperature; NTC/PTC thermistors change semiconductor resistance; Temperature diodes have a forward bias voltage proportional to temperature; Infrared sensors detect Infrared radiation from a target object; silicon sensor converts temperature using analog or digital technology.

The principle of temperature sensor

The temperature sensor is a device that measures temperature and converts it into an electrical signal . It is widely used in various industrial, scientific and consumer fields. The following describes how several common temperature sensors work:

1. Thermocouple

A thermocouple is made of two different metals that are connected together . When there is a temperature difference between the thermocouple's connection point and the measurement point, a thermoelectric potential is generated between the two metals. The thermoelectric potential is proportional to the temperature difference and can be measured with an electric meter.

2. Resistance Temperature Detector (RTD)

RTD is a metal resistor whose resistance changes with temperature. RTDs are typically made from materials such as platinum, copper, or nickel. As the temperature increases, the resistance value of the RTD also increases.

3. Thermistor (NTC/PTC)

NTC (negative temperature coefficient) and PTC (positive temperature coefficient) thermistor are semiconductor resistors. The resistance value changes with temperature. The resistance value of an NTC thermistor decreases as the temperature increases, whereas the resistance value of a PTC thermistor increases as the temperature increases.

4. Temperature diode

The temperature diode is a semiconductor diode whose forward bias voltage is proportional to the temperature. As the temperature increases, the forward bias voltage of the diode also increases.

5. Infrared temperature sensor

The infrared temperature sensor measures the temperature by measuring the infrared radiation emitted by the target object. The intensity of infrared radiation is directly proportional to the temperature of the object. Pyroelectric detectors in the sensor convert infrared radiation into electrical signals.

6. Silicon temperature sensor

A silicon temperature sensor is an integrated circuit (IC) that uses analog or digital technology to convert temperature into an electrical signal. Such sensors typically have high accuracy and fast response times.

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