Description
Class G01R : MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
Subclass 1/28: Details of instruments or arrangements of the types included in groups G01R 5/00-G01R 13/00 and G01R 31/00 (constructional details particular to arrangements for measuring the electric consumption G01R 11/02) Provision in measuring instruments for reference values, e.g. standard voltage, standard waveform