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A moving coil galvonometer of resistance R_G gives a full scale deflection when a current I_g flows through its coil. It can be converted into an ammeter of range 0 to I(I > I_g) when a shunt of resistance S is connected across its coil. If this galvanometer is converted into an ammeter of range 0 to 2I, find the expression for the shunt required in terms of S and and R_G. |
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Answer» Solution :If a moving coil galvonometer of resistance `R_G`gives full scale deflection for acurrent `I_g`, it can be converted into an ammeter of MAXIMUM range I by connecting a shunt of resistance S, where `S = (R_G . I_g)/(I - I_g) implies SI = (R_G + S) I_(g)"" ....(i)` To CONVERT the GIVEN galvonometer into an ammeter of maximum range 2I we shall connect a shunt of resistance `S.`, where `S. = (R_G CDOT I_g)/(2I- I_g) implies S.. 2I = (R_G + S.) I_(g) "" ....(ii)` From (ii) and (i), we get `(2S.)/(S) = (R_(G) + S.)/(R_G + S) implies S. = (S . R_g)/((S + 2R_g))`. |
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