Inductors

Inductors

1. DEFINITION

   • An Inductor is a passive electrical component consisting of a coil of wire which is designed to take advantage of the relationship between magentism and electricity as a result of an electric current passing through the coil

2. symbols

   • Like any other electronic, inductors have symbols that allow their identification in circuit diagrams

3. How does it work?

   • The current, i that flows through an inductor produces a magnetic flux that is proportional to it. But unlike a Capacitor which oppose a change of voltage across their plates, an inductor opposes the rate of change of current flowing through it due to the build up of self-induced energy within its magnetic field.

4. Inductance

   • DEFINITION
     • Inductance is the ability of an inductor to store energy and it does this in the magnetic field that is created by the flow of electrical current.
       • UNITS
         • Inductance is given the symbol L with units of Henry, (H) after Joseph Henry.
       • Formulas
         • Faraday's Law
           • An inductor coil has a central core area, ( A ) with a constant number of turns of wire per unit length, ( l ). So if a coil of N turns is linked by an amount of magnetic flux, Φ then the coil has a flux linkage of NΦ and any current, ( i ) that flows through the coil will produce an induced magnetic flux in the opposite direction to the flow of current. Then according to Faraday’s Law, any change in this magnetic flux linkage produces a self-induced voltage in the single coil of:
         • Energy Stored
           • When power flows into an inductor, energy is stored in its magnetic field. When the current flowing through the inductor is increasing and di/dt becomes greater than zero, the instantaneous power in the circuit must also be greater than zero, ( P > 0 ) ie, positive which means that energy is being stored in the inductor.
         • Impedance
           • Impedance (symbol Z) is a measure of the overall opposition of a circuit to current, in other words: how much the circuit impedes the flow of charge. It is like resistance, but it also takes into account the effects of capacitance and inductance. Impedance is measured in ohms (ohm).
         • Lenz's Law
           • Lenz's law states that the direction of an induced e.m.f. will be such that if it were to cause a current to flow in a conductor in an external circuit, then that current would generate a field that would oppose the change that created it.

5. Applications

   • * Energy Storage Devices. * Induction Motors * Transformers * Inductive Filters * Choke * Ferrite beds * Relays

6. Inductors in Series and Parallel

Images and files in the map

• Inductor basics - What is an inductor? (Embed)
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