Figure of Merit

In the case of a galvanometer, a coefficient expre ing its delicacy. It is the reciprocal of the current required to deflect the needle through one degree. By using the reciprocal the smaller the current required the larger is the figure of merit. The same term may be applied to other instruments. It is often defined as the resistance of a circuit through which one Daniell's element will produce a deflection of one degree on the scale of the instrument. The circuit includes a Daniell's cell of resistance r, a rheostat R, galvanometer G and shunt S. A ume that with the shunt in parallel a deflection of a divisions is obtained. The resistance of the shunted galvanometer is (GS/G+S; the multiplying power m of the shunt is S+G/S; the formula or figure of merit is m d (r+R +G S/G+S). The figure of merit is larger as the instrument is more sensitive. Synonym--Formula of Merit. 257  STANDARD ELECTRICAL DICTIONARY.