Explain Design an ammeter with a galvanometer inside of it and a shunt resistor.

Question

Explain

Design an ammeter with a galvanometer inside of it and a shunt resistor. The galvanometer resistance is 10 ohms. Make sure you explain the answers and show all the equations for full credit. The galvanometer is only capable of measuring currents that are less than 100 times l0^ - 6 A. How you can use a shunt resistor in the galvanometer to measure a current that is much larger than the full scale deflection current of the galvanometer? Draw a circuit diagram showing the galvanometer, its internal resistance Rg, and how the shunt resistor, Rg has to be wired into the circuit to protect the galvanometer from being fried. Derive the necessary equations. Will the shunt resistor have to be much smaller or much larger than the resistance of the galvanometer coil, Rg? Explain the reason for your answer. What value of shunt resistance will you need to measure a maximum current of 1.0 A?

Explanation / Answer

a) we connect a small shunt resistor parallel to the galvanometer.

let Rs is the shunt resistor.

Rnet = Rs*Rg/(Rs+Rg)

current through galvanometer,ig = I*(Rs/(Rs+Rg))

current through shunt resistor,is = I*(Rg/(Rs+Rg))

here Rs<<Rg ==> is >> ig

so, most of the current flows through shunt resostor.


b) shunt resistor should much smaller as i have explained above.

c)

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