DDYS22Dx series single-phase prepayment electricity meter adopts the most advanced dedicated integrated circuit design, fully automatic surface mount (SMT) and hot air reflow welding production process manufacturing. The circuit design and component selection of the electricity meter are based on a larger environmental tolerance to ensure the long-term stable operation of the whole machine, high precision, high overload, low power consumption, and high reliability. It adopts IC card technology that meets international standards to achieve prepayment, and has a built-in relay. By controlling the relay to control the on and off of the load, it realizes the function of urging users to buy electricity before using electricity.