Applications and principles of temperature sensors:
A thermoelectric sensor is a device that converts a measured quantity (mainly temperature) into a change in electrical quantity. This conversion is based on the thermoelectric effect of metals. Depending on the conversion method, they can be divided into thermocouples and resistance temperature detectors (RTDs). All thermocouples are further classified into thermocouple-type temperature sensors and RTD-type temperature sensors.
1.1 Application Principle of Temperature Sensor Thermocouple
Vilink temperature sensors and thermocouples are commonly used temperature sensing elements in industry. Their advantages are:
① High measurement accuracy. Because the temperature sensor thermocouple is in direct contact with the object being measured, it is not affected by the intermediate medium.
② Wide measurement range. Commonly used temperature sensor thermocouples can continuously measure from -50 to +1600℃, and some special temperature sensor thermocouples can measure as low as -269℃ (such as gold-iron-nickel-chromium) and as high as +2800℃ (such as tungsten-rhenium).
③ Simple construction and easy to use. Temperature sensor thermocouples are usually composed of two different metal wires, and are not limited by size or shape. They are also protected by a sheath, making them very convenient to use.
1.2 Basic Principle of Temperature Measurement by Continuous Thermocouple Temperature Sensor
Two conductors or semiconductors, A and B, made of different materials, are welded together to form a closed circuit. When a temperature difference exists between the two junctions 1 and 2 of conductors A and B, an electromotive force is generated between them, thus forming a current in the circuit. This phenomenon is called the thermoelectric effect. Thermocouples, temperature sensors, utilize this effect to function.
1.3 Types and Structure of Temperature Sensor Thermocouples
(1) Types of thermocouple temperature sensors
Commonly used temperature sensors, such as thermocouples, can be divided into two main categories: standard temperature sensors and non-standard temperature sensors.
The standard temperature sensor thermocouples referred to are those whose thermoelectric potential-temperature relationship, permissible error, and standardized calibration table are specified by national standards, and which have matching display instruments available for selection. Non-standardized temperature sensor thermocouples are inferior to standardized temperature sensor thermocouples in terms of application range or quantity, and generally do not have standardized calibration tables, mainly used for measurements in certain special applications. In my country, since January 1, 1988, all temperature sensor thermocouples and resistance temperature sensors have been manufactured according to IEC national standards, and seven standardized temperature sensor thermocouples (S, B, E, K, R, J, and T) have been designated as the unified design type of temperature sensor thermocouples in my country.
(2) The structure of temperature sensor thermocouple
To ensure the reliable and stable operation of the temperature sensor thermocouple, its structural requirements are as follows:
① The welding of the two thermocouples that make up the temperature sensor must be firm:
② The two thermoelectrodes should be well insulated from each other to prevent short circuits:
③ The connection between the compensating wire and the free end of the thermocouple of the temperature sensor should be convenient and reliable;
④ The protective sleeve should be able to ensure that the thermoelectric electrode is fully isolated from the harmful medium.
Weilian Electronics' thermistor sensors are used in new energy vehicles. Weilian Electronics is an electronic component brand integrating R&D, design, production, and sales. With over 20 years of experience in the electronics industry and long-term cooperation with research institutes and universities, we can customize parameters and dimensions according to customer requirements, focusing on specific customer needs (electromechanical compatibility, electronic product modification and upgrades, solution provision, etc.).
