D.C. Circuits Concepts and Circuit Elements For Students

What is the Inductance

Inductance is also an energy storing element like capacitor. The energy stored in the inductance is in the form of Electromagnetic Field. Both Inductance can also be used in wave shaping circuits.

Inductance is also called as Inductor. Inductance exhibits delay in the rise and fall of currents through it. Hence, it is used to represent a mass possessing inertia in Electrical Analog Circuits used to represent a Mechanical System.

A current flowing through a conductor sets up an electromagnetic field around the conductor.

The direction of the magnetic field setup is given by, Maxwell’s Right Hand Cork-Screw Rule or Right Hand Threaded Screw Rule which states that, the direction of the magnetic field setup by a current flowing through a conductor will be given by the direction of rotation of a right hand cork-screw if the screw is to advance in the direction of the current flow.

Hence, it will be circular around the conductor as given in the Figure 1.

Note: The dot inside the conductor of Figure 1 represents the arrow head and indicates that the current is directed towards us i.e., away from the plane of the paper.

Magnetic field of a solenoid

In the Figure 2(b) and Figure 2(c), the conductor is shown by circular cross-section with a dot or cross inside to indicate the direction of the current.

The circle around the conductor along with its direction indicates the direction of the magnetic field setup by the current flowing through this conductor. If a coil is wound on a soft iron rod, as in Figure 2 and connected to a battery, the steel becomes magnetized and behaves like a temporary magnet.

This magnetic field of the electromagnet is represented by the dotted lines and its direction by the arrow heads.

The direction of the magnetic field produced by a current in a solenoid may be deduced by applying either the Right Hand Threaded Screw or the Right Hand Grip Rule.

If the axis of the screw is placed along that of the solenoid and if the screw is turned in the direction of the current, it travels in the direction of the magnetic field inside the solenoid, namely towards the right in Figure 3.

The cross inside the conductor of Figure 1 represents the tail of an arrow and indicates that the current is directed away from us i.e., into the plane of the paper.