In the PMMC type instrument, the deflection is directly proportional to the current flowing through the instrument, we get a uniform scale for the instrument. It gives a uniform scale of upto 270° or more. Td ∝ I
Magnetic Field Strength (H) gives the quantitative measure of strongness or weakness of the magnetic field. H = B/μo Where B = Magnetic Flux Density μo = Vacuum Permeability The magnetic Field strength at the center of circular loop carrying current I is given by B = μoI/2r B/μo = I/2r H = I/2r At/m Where r = Radius