Traditional electromechanical electricity meters, commonly used for many years, are essentially analog devices. They measure instantaneous power (voltage multiplied by current) and integrate it over time to calculate the total energy consumed. This process of integrating a continuously varying signal (power) over time is a form of analog computation, where a physical quantity (like the rotation of a disk) represents the cumulative energy. While modern smart meters are digital and incorporate microcomputers, the question likely refers to the fundamental nature or a common type of electricity meter as a device that processes continuous electrical signals to compute energy.