Me student of class 12 want meterial for investigatory project.with observationas and calculations as done in any experiment..."to study the facors on the self inductance of coil when put in series with resistance"
Plz this is my project help me !!!!
Date:7 /8/16
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The property of self-inductance is a particular form of electromagnetic induction. Self inductance is defined as the induction of a voltage in a current-carrying wire when the current in the wire itself is changing. In the case of self-inductance, the magnetic field created by a changing current in the circuit itself induces a voltage in the same circuit. Therefore, the voltage is self-induced.
The term inductor is used to describe a circuit element possessing the property of inductance and a coil of wire is a very common inductor. In circuit diagrams, a coil or wire is usually used to indicate an inductive component. Taking a closer look at a coil will help understand the reason that a voltage is induced in a wire carrying a changing current. The alternating current running through the coil creates a magnetic field in and around the coil that is increasing and decreasing as the current changes. The magnetic field forms concentric loops that surround the wire and join to form larger loops that surround the coil as shown in the image below. When the current increases in one loop the expanding magnetic field will cut across some or all of the neighboring loops of wire, inducing a voltage in these loops. This causes a voltage to be induced in the coil when the current is changing.
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SELF INDUCTION
Self induction is that phenomenon in which a change in electric current in a coil produces an induced emf in the coil itself.
MATHEMATICAL REPRESENTATION:
Self induced emf in a coil is directly proportional to the rate of change of electric current in the coil.i.e.
Emf a – DI/Dt
Or emf = -L DI/Dt
Where, L = self inductance of the coil.
SELF INDUCTANCE
Self inductance of a coil is defined as the ratio of self-induced emf to the rate of change of current in the coil.
Self inductance = emf/ DI/Dt
It is denoted by ‘L’ and it depends upon the physical characteristics of the coil.
Unit of self inductance is Henry.
HENRY
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The self inductance of a coil is one henry if a current change of one ampere per second through it produces an emf of one volt in it.
If a changing flux is linked with a coil of a conductor there would be an emf induced in it. The property of the coil of inducing emf due to the changing flux linked with it is known as inductance of the coil. Due to this property all electrical coil can be referred as inductor. In other way, an inductor can be defined as an energy storage device which stores energy in form of magnetic field.
Theory of Inductor
A current through a conductor produces a magnetic field surround it. The strength of this field depends upon the value of current passing through the conductor. The direction of the magnetic field is found using the right hand grip rule, which shown. The flux pattern for this magnetic field would be number of concentric circle perpendicular to the detection of current.
Now if we wound the conductor in form of a coil or solenoid, it can be assumed that there will be concentric circular flux lines for each individual turn of the coil as shown. But it is not possible practically, as if concentric circular flux lines for each individual turn exist, they will intersect each other. However, since lines of flux cannot intersect, the flux lines for individual turn will distort to form complete flux loops around the whole coil as shown. This flux pattern of a current carrying coil is similar to a flux pattern of a bar magnet as shown.
inductor
Now if the current through the coil is changed, the magnetic flux produced by it will also be changed at same rate. As the flux is already surrounds the coil, this changing flux obviously links the coil. Now according to Faraday’s law of electromagnetic induction, if changing flux links with a coil, there would be an induced emf in it. Again as per Lenz’s law this induced emf opposes every cause of producing it. Hence, the induced emf is in opposite of the applied voltage across the coil.
Definition of Self Inductance
Whenever, current flows through a circuit or coil, flux is produced surround it and this flux also links with the coil itself. Self induced emf in a coil is produced due to its own changing flux and changing flux is caused by changing current in the coil. So, it can be concluded that self-induced emf is ultimately due to changing current in the coil itself. And self inductance is the property of a coil or solenoid, which causes a self-induced emf to be produced, when the current through it changes.
Explanation of Self Inductance of a Coil
