An inductor is a passive two-terminal electrical component that stores energy in its magnetic field. Inductors square measure designed to line up a powerful field linking the unit, whereas capacitors square measure designed to line up a powerful field of force between the plates. Inductance is measured in Henries (H). One Henry is that the inductance level that may establish a potential unit of one volt across the coil because of a modification in the current of one A/s through the coil.

Inductors have a variety of response characteristics almost like those of the electrical condenser. The inductance exhibits its true characteristics only an amendment in voltage or current is formed within the network.

Basic Inductors

  • They store energy in a magnetic field
  • An inductor is essentially a coil of wire with an iron core.
  • The symbol for an inductor is:

What do inductors do?

  • Consider this circuit
  • What will happen once the switch is closed?
  • Lamp A can glow instantly
  • Lamp B can take your time to achieve full brightness.


  • As the current starts to flow through the inductance, a magnetic flux starts to create around it…..
  • As this field forms, the magnetic flux lines pass the coils within the inductance and induce a voltage across the inductor….
  • According to Lenz’s Law, this voltage can oppose the voltage that caused it…..
  • This opposing voltage restricts this build-up within the circuit thus it takes a jiffy for the bulb to succeed in full brightness.

An inductor is made of a coil of conducting wire

Magnetic Fields

  • In the region close a magnet there exists a magnetic flux, which might be portrayed by magnetic flux lines the same as electrical flux lines.
  • Magnetic flux lines take issue from electrical flux lines in this they don’t have associate origin or termination purpose.
  • Magnetic flux lines radiate from the pole to the South Pole through the magnetic bar.
  • Continuous magnetic flux lines can attempt to occupy as tiny apart as potential.
  • The strength of a flux in a very given region is directly associated with the density of flux lines therein region.
  • If not like poles of 2 permanent magnets square measure brought along the magnets can attract, and also the flux distribution is as shown below.

If like poles square measure brought along, the magnets can repel, and therefore the flux distribution is as shown.
If a nonmagnetic material, like glass or copper, is placed within the flux methods close a magnet, there’ll be AN nearly unnoticeable modification within the flux distribution.

If a magnetic material, like soft iron, is placed within the flux path, the flux lines can have the soft iron instead of the encompassing air as a result of the flux lines pass with larger ease through magnetic materials than through air. This principle place to use within the shielding of sensitive electrical components and instruments that may be laid low with stray magnetic fields.

The direction of the magnetic flux lines is found by putting the thumb of the correct hand within the direction of typical current flow and noting the direction of the fingers (commonly referred to as the correct hand rule).

The relation between the flux in inductance and therefore the current through the inductance is given below.