In electrical circuits for monitoring, protection or control, a temperature sensor is widely used . It is necessary to adjust the thermal conditions during the operation of various equipment in production. Such devices are widely used in household appliances: washing machines, televisions, computers, etc. Using a temperature sensor allows you to avoid many accidents and save expensive equipment in the workplace and at home.
These devices convert the measured temperature of the object into an analog or relay signal, understandable for receiving equipment. They differ in the way the thermal signal is converted and come in several forms:
- It has long been known that when the temperature changes, the internal resistance of the materials changes. On the basis of this, thermoresistive temperature sensors were created. This type of temperature sensor has small dimensions and good performance. It is in good agreement with work in low-current circuits with electronic circuits that emit any change in resistance and use the received signal for further conversion. The disadvantages include the nonlinearity of the characteristic, which leads to a complication of the schemes for changing the received signal.
- Semiconductor temperature sensors work on the same principle, but they are much more sensitive than thermoresistive ones. They have a linear characteristic, they are easy to make at home. The disadvantages include a small range of measured temperature (-55 - +155).
- Thermoelectric converters are widely used in production, for example, in electric arc furnaces for process control. Thermocouples of platinum or tungsten groups have a wide temperature range. They can operate normally under conditions exceeding the melting point of many metals. This type of temperature sensor can be found in everyday life, it can be used to control the temperature in the sauna.
- For remote temperature measurement , special devices are used that record thermal waves emanating from heated bodies. This type of temperature sensor is called a pyrometer. The disadvantages of such devices include frequent distortion of the temperature field and a decrease in the stability of the device itself.
- Acoustic sensors are used for measurements in gas and other environments. They can be useful where contact measurement methods are not possible. The principle of their operation is based on a change in the speed of propagation of acoustic waves in variously heated media. Temperature sensors of this type have a large error. Repeated measurements are often required to refine measurement results.
All of the above temperature sensors are widely used in the design and creation of electronic devices of varying degrees of complexity. Without them, the functioning of most of the circuits becomes impossible, and much depends on their stable operation. When designing the most critical units based on these elements, duplication of the readings of various sensors is often used.