... national standards & regulations. Without matching an external standard meter, it can automatically or manually calibrate and test class ... AC/DC voltmeter, and power meter. Besides, it can also calibrate frequency meter, phase meter, power factor meter, transducer, power load transformer, ... 15VA;3.13. Power supply: 220V±10%, 50Hz±1%;3.14. Working environment: -5~35°; relative humidity≤85%;3.15 ...