1. Summary : AC/AV transducers can convert the measured AC/AV into liner DC/DV output. They can be applied widely in the fields of electric power, telecom, oil, colliery, metallurgy, railway, city planning and so on. AC/AV transducers have two structures, single and three-combined. The characters are: 1) High accuracy; 2) High linearity of total measuring range; 3) High integration, simple structure, good temperature ’ s character and long-term stability.