Two moving coil meters, M1 and M2 have the following particulars:
R1=10Ω,N1=30
A1=3.6×10−3m2,B1=0.25T
R2=14Ω,N2=42
A2=1.8×10−3,B2=0.50T
(The spring constants are identical for the two meters).Determine the ratio of (a) current sensitivity and (b) voltage sensitivity of M2 and M1.
(a)Current sensitivity of
M1 is given as,
Is1=N1B1A1/k1
Is2=N2B2A2/k2
where,
N=turns,
B=Magnetic field,
k=spring constant,
A=area
R=Electric resistance.
Is1/Is2=1.4
(b)
Voltage
sensitivity relation is given as,
Vs1=N1B1A1/k1R1
Vs2=N2B2A2/k2R2
where,
N=turns,
B=Magnetic
field,
k=spring
constant,
A=area
R=Electric
resistance.
Vs1/Vs2=1