Physics and circuitry of construction and functioning of modern pyrometers including energy pyrometers and spectral ratio pyrometers are considered. Considerable attention is paid to the modern element base - microprocessors and microcontrollers, the features of their use in measuring equipment. Examples of construction of pyrometer assemblies on elements of microprocessor technology are given. Issues of metrological support of pyrometry, reference base, verification schemes, as well as peculiarities of application and correction of modern spectral ratio pyrometers, their advantages over energy pyrometers are considered.