DIN EN 60051-2-1991 直接顯示的模擬電器測量儀及附件.第2部分:電流表及電壓表的特殊要求(IEC 51-2-84.第4版)
Direct acting indicating analogue electrical measuring instruments and their accessories; part 2: special requirements for ammeters and voltmeters (IEC 60051-2:1984, edition 4); german version EN 60051-2:1989