The temperature indication is displayed by measuring the electricity or voltage of the light bulb filament. According to the Analysis and Testing Encyclopedia website, the function of the optical pyrometer electrical measurement system is to display the temperature indication by measuring the electricity or electricity of the light bulb filament. Optical pyrometer bulbs are used for precision testing in scientific experiments, and standard optical pyrometers are used for the transfer of quantitative values, such as in the determination of melting point, heat capacity and phase change point of substances.