A pyrometer is an infrared thermometer that measures the temperature of thermal radiation without contact. In general, any object
emits infrared radiation. All bodies whose temperature is above absolute zero. Pyrometers detect the infrared radiation of objects. The central component of a pyrometer is an infrared sensor or pyrosensor made of pyroelectric crystals. The infrared sensors used have their highest spectral sensitivity in the infrared range between wavelengths of 1 µm to 20 µm. For better utilization of the thermal radiation, there is a converging lens in front of the infrared sensor, with which the thermal radiation is focused on the IR sensor. This can be a Selfoc lens or a Fresnel lens. Depending on the heat radiation, the IR sensor generates an electrical voltage by means of pyroelectricity, which is amplified by a highly sensitive amplifier and further processed in the downstream electronics. The processed heat signal is shown on a display
and can be used to display it on thermal imaging cameras or to control other components.reflection by external radiation and the radiation by transmission. This is the thermal radiation that penetrates the body.