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leena19
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Homework Statement
3)An ammeter has a full scale deflection of 0.5 A.Internal resistance is 12 ohms.Explain with necessary calculations,how it should be converted to an ammeter of full scale deflection 2A.
4) does this modification change the sensitivity of the instrument?explain
5. The modified ammeter is connected to the circuit given in the diagram to measure the current through the appliance of resistance 1 ohm
a. what is the current through the appliance?
b. what is the reading shown by the ammeter?
c. calculate the potential difference between points C & F
http://img199.imageshack.us/img199/793/ammeter.png [Broken]
Homework Equations
Kirchoff's laws
The Attempt at a Solution
1) T find the shunt resistance(R),
0.5*12 = 1.5*R
R=4 ohms
2) sensitivity = deflection([tex]\theta[/tex] per unit current(I)
so I = C(torsion constant of springs)/BAN[tex]\theta[/tex]
so sensitivity=BAN/C,
looks as though the current has no effect on the sensitivity ,so I guess the answer is no?
3) a.) since the current through the ammeter is 0.5A,and the current throgh the shunt is 1.5A,the current through the appliance,should be 2A?
b) 0.5A?
c) Is it correct to take the potentials,
VDE = VCF &
(2*1) +( 0.5*12)= 8V
I'm very very doubtful of this part,cause if I do it like this ,I won't be using any of the other values given in the circuit,and it looks a bit odd?
THANK YOU
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