... related 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, and ... ~360°, with fine regulation 0.1°;3.5. Phase angle symmetry degree 120°±0.5°(3P4W voltage); 60°±0.5 ...