This part of IEC 60051 specifies definitions and general requirements for direct acting indicating analogue electrical measuring instruments and their accessories. This part applies to direct acting indicating analogue electrical measuring instruments, such as: ammeters and voltmeters; wattmeters and varmeters; frequency meters of pointer and vibrating-reed types; phasemeters, power-factor meters and synchroscopes; ohmmeters(impedance meters) and conductance meters; multi-function instruments of the above types. It also applies to; certain accessories used with these instruments, such as; shunts; series resistors and impedance elements; combination of the instruments and the accessories provided that the adjustments have been made for the combination; direct acting indicating electrical measuring instrument whose scale marks do not correspond directly to its electrical input quantity, provided that the relationship between them is known; instruments and accessories having electronic devices in their measuring and/or auxiliary circuits. These series standards do not apply to; special purpose instruments which are covered by their own IEC standards; special purpose devices which are covered by their own IEC standards when they are used as accessories. This standard does not specify requirements concerning dimensions of instruments or accessories (for the former, see IEC 60473).