What Is a Temperature Transducer?

A temperature sensor is a sensor that can sense temperature and convert it into a usable output signal. The temperature sensor is the core part of the temperature measuring instrument. According to the measurement method, it can be divided into two types: contact type and non-contact type. According to the characteristics of the sensor material and electronic components, it is divided into two types: thermal resistance and thermocouple.

Sensor designed with metal expansion principle

Metals produce a corresponding extension after changes in ambient temperature, so sensors can signal-transform this response in different ways.

Bimetal sheet sensor

The bimetal sheet is composed of two pieces of metal with different expansion coefficients stuck together. As the temperature changes, the material A expands more than the other metal, causing the metal sheet to bend. The curvature of the bend can be converted into an output signal.

Bi-Metal Rod and Metal Tube Sensor

As the temperature increases, the length of the metal pipe (material A) increases, while the length of the non-expanded steel rod (metal B) does not increase, so that due to the change in position, the linear expansion of the metal pipe can be transmitted. In turn, this linear expansion can be converted into an output signal.

Sensor for liquid and gas deformation curve design

When the temperature changes, the liquid and gas will also change the volume accordingly.

Many types of structures can convert this change in expansion into a change in position, which produces a change in position output (potentiometer, induction deviation, baffle, etc.).

If you want to make a reliable temperature measurement, you first need to choose the right temperature instrument, that is, a temperature sensor. Among them, thermocouple, thermistor, platinum resistance (RTD) and temperature IC are the most commonly used temperature sensors in the test.

The following are the characteristics of two types of temperature instruments, thermocouple and thermistor.

1.Thermocouple

Thermocouples are the most commonly used temperature sensors in temperature measurement. Its main benefits are wide temperature range and adaptability to various atmospheric environments,

1.Does the temperature of the measured object need to be recorded?

Temperature sensor verification procedures:

1. "JJG229-2010 Industrial Platinum,

When installing and using the temperature sensor, you should pay attention to the following items to ensure the best measurement results:

1. Errors introduced by improper installation

For example, the location and insertion depth of the thermocouple cannot reflect the true temperature of the furnace.

In recent years, the process of China's industrial modernization and the continuous rapid growth of the electronic information industry,

Temperature is a physical quantity that characterizes the coldness and heatness of an object. It is an important and universal measurement parameter in the process of industrial and agricultural production. Temperature measurement and control play a very important role in ensuring product quality, improving production efficiency, saving energy, production safety, and promoting the development of the national economy. Due to the universality of temperature measurement, the number of temperature sensors ranks first among various sensors, accounting for about 50%.

Temperature sensors measure indirectly by changing certain characteristics of an object as the temperature changes. The characteristics of many materials and components change with temperature, so there are quite a few materials that can be used as temperature sensors. Temperature sensors cause physical parameter changes with temperature: expansion, resistance, capacitance, and electromotive force, magnetic properties, frequency, optical characteristics, thermal noise, and so on. With the development of production, new temperature sensors will continue to emerge.

Due to the extremely wide range of temperature measurement in industrial and agricultural production, from several hundred degrees below zero to several thousand degrees above zero, temperature sensors made of various materials can only be used within a certain temperature range.

The contact methods of the temperature sensor and the measured medium are divided into two categories: contact and non-contact. The contact temperature sensor needs to maintain thermal contact with the measured medium, so that the two can conduct sufficient heat exchange to reach the same temperature. This type of sensor mainly includes resistance type, thermocouple, PN junction temperature sensor and so on. The non-contact temperature sensor does not need to be in contact with the measured medium, but is transmitted to the temperature sensor through the heat radiation or convection of the measured medium to achieve the purpose of temperature measurement. This type of sensor mainly includes infrared temperature sensors. The main characteristic of this temperature measurement method is that it can measure the temperature of substances in motion (such as the temperature of a bearing of a slow-moving train, the temperature of a rotating cement kiln) and objects with small heat capacity (such as the temperature distribution in an integrated circuit).

Temperature sensor ^[2] is the earliest developed and most widely used type of sensor. The market share of temperature sensors greatly exceeds other sensors. Since the beginning of the 17th century, people have used temperature to measure. With the support of semiconductor technology, semiconductor thermocouple sensors, PN junction temperature sensors, and integrated temperature sensors have been successively developed this century.
If two kinds of conductors of different materials are connected to each other at a certain point, if the connection point is heated, a potential difference will appear at the parts where they are not heated. The value of this potential difference is related to the temperature of the measurement point in the unheated part, and to the material of these two conductors. This phenomenon can occur in a wide temperature range. If this potential difference is accurately measured, and then the ambient temperature of the unheated part is measured, the temperature of the heating point can be accurately known. Because it must have two different material conductors, it is called a "thermocouple". Thermocouples made of different materials are used in different temperature ranges, and their sensitivity is also different.
Thermocouple sensors have their own advantages and disadvantages. They have low sensitivity, are easily affected by environmental interference signals, and are also easily affected by temperature drift of the preamplifier, so they are not suitable for measuring small temperature changes. Since the sensitivity of the thermocouple temperature sensor is independent of the thickness of the material