DDSY type (IC card) single phase electronic prepayment watt-hour meter sthe new generation intelligent meter with advanced static integrated technology and SMT craft. Its performance accord with class 1.0 single phase electri- caI meter Of JB/T8382-96. They feature advanced principle. Compact structure high accuracy and sensitivity, well reliability, long service life, anti-power theft strong overload, IC card prepayment, alarming of remainder charge, storing data for over10 years setting secret muIti-grade and so on.