... national standards & regulations. Without matching an external standard meter, it can automatically or manually calibrate and test ... 3-phase AC/DC ammeter, AC/DC voltmeter, and power meter. Besides, it can also calibrate frequency meter, phase meter, power factor meter, transducer, ... frequency;2.3. Multi-function standard meter with power, electric energy, AC/DC voltage, AC/DC current standards;2.4. DC ...