The main component of the thermistor sensor is the thermistor. When there is heat radiation around the heat-sensitive material, it will absorb the radiant heat and generate a temperature increase, which will cause the resistance of the material to change.
As a thermistor sensor for measuring temperature, the general structure is simpler and the price is relatively low. The thermistor without an outer protective layer can only be used in a dry place. The sealed thermistor sensor is not afraid of moisture erosion and can be used in harsh environments. Because the resistance of the thermistor sensor is relatively large, the resistance and contact resistance of its connecting wire can be ignored. Therefore, the thermistor sensor can be used to measure temperature at a distance of several kilometers, and the measurement circuit mostly uses a bridge circuit. Another product used for temperature measurement is ntc thermistors for temperature measurement.
The thermistor sensor can compensate the humidity of certain components within a certain temperature range. For example, the moving coil in the head of a moving-coil meter is made of copper wire. As the temperature rises, the resistance increases, causing temperature errors. Therefore, the thermistor sensor working with negative temperature coefficient can be connected in parallel with the manganese copper wire resistance in the loop of the moving coil and then connected in series with the compensated component to offset the error caused by the temperature change. In transistor circuits and logarithmic amplifiers, thermistor sensors are also commonly used to form compensation circuits. Compensate for drift errors caused by temperature.
The operation of thermistor should be very careful.Overheating protection is divided into direct protection and indirect protection. For small current occasions, the thermistor sensor can be directly connected to the load to prevent overheating damage and protect the device. For large current occasions, it can be used to protect relays, transistor circuits, etc. In either case, the thermistor is tightly integrated with the protected device, so that there is sufficient heat exchange between the two. Once overheated, the thermistor plays a protective role.