A rectangular moving coil of a milliammeter is wound with 30 turns. The effective axial length of the magnetic field is 20 mm and the effective radius of the coil is 8 mm. The flux density in the gap is 0.12 T and the controlling torque of the hairsprings is 0.5 × 10-6 N m/ degree of deflection. Calculate the current to give a deflection of 60°.
Ampere Circuital Law
Ampere's Law states that "for any closed loop path, the sum of the length elements times the magnetic field in the direction of the length element is equal to the permeability times the electric current enclosed in the loop.”
Current Density
To design the electrical and electronic system, the current density is an important factor. The designer current level is the factor on which the circuit performance depends and with the help of the dimensions of the conducting current the current density is then determined. For instance, despite the lower current demanded by smaller devices as integrated circuits are reduced in size, there is a type of trend in achieving the higher device number in even smaller chip areas. The current density is increased in this region at higher frequencies because the conducting region in a wire becomes confined and this is known as the skin effect. The consequences increase as the current densities become higher.
A rectangular moving coil of a milliammeter is wound
with 30 turns. The effective axial length of the magnetic field is 20 mm and the effective radius of the coil
is 8 mm. The flux density in the gap is 0.12 T and the
controlling torque of the hairsprings is 0.5 × 10-6 N m/
degree of deflection. Calculate the current to give a
deflection of 60°.
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