A physical thermometer can be understood as a compariso […]
A physical thermometer can be understood as a comparison of mercury (thermometer) and electronic thermometer. Generally speaking, the working principle of a physical (mercury) thermometer is that the thermal expansion of mercury is proportional to temperature. Because mercury has a compact structure, its performance is very stable, and the coefficient of thermal expansion is constant when sealed in a thermometerPunching metal parts Manufacturers. Therefore, mercury (physical) thermometers have the characteristics of accurate indication and high stability.
The electronic thermometer uses the thermoelectric power generated by the thermal sensor to determine the temperature. Due to the problems of zero drift and cold junction compensation in thermal sensors, low-grade electronic thermometers may have lower accuracy.
The electronic thermometer senses the temperature change according to the temperature-sensing material, and then converts it into a city signal, which is then detected by the circuit chip and converted into a numerical display. After many steps, the data is an approximate value with a certain error, which is even larger when the battery is insufficient. The direct reading of the indoor thermometer has few links and the error is relatively small.
Thermocouple thermometer is a temperature measuring instrument widely used in industry. Consists of thermoelectric phenomena. Two different metal wires are welded together to form a working end, and the other two ends are connected with the measuring instrument to form a circuit. When the working end is placed at the measured temperature, when the temperature of the working end is different from the temperature of the free end, an electromotive force will appear, and a current will flow through the circuit. By measuring electricity, you can use the known temperature to measure the temperature of another place. It is suitable for the measurement of high temperature and low turbidity between two substances with large temperature difference. Some thermocouples can measure high temperatures up to 3000°C, while others can measure low temperatures close to absolute zero.
Pointer thermometer: It is a thermometer shaped like a dashboard, also called a thermometer. It is used to measure room temperature and is made using the principle of metal thermal expansion and contraction. It uses bimetal as a temperature sensing element to control the pointer. Bimetals are usually riveted with copper and iron sheets, with copper sheets on the left and iron sheets on the right. Because the thermal expansion and contraction effect of copper is much more obvious than that of iron, when the temperature rises, the copper sheet pulls the iron sheet to bend to the right, and the bimetallic sheet drives the pointer to deflect to the right (pointing to high temperature); on the contrary, when the temperature becomes lower, The pointer deflects to the left (pointing to low temperature) driven by the bimetal.