Inductor

Inductors are used in many analog circuits and are also used along with capacitors for forming filter circuits and thus signal processing. They are also used in Switched Mode Power Supplies (SMPS), oscillators, transmitters, receivers, voltage regulators and also for over voltage protection.

What is an Inductor?

An Inductor, also known as a reactor is simply a coil of wire, which has many electrical properties when subjected to a magnetic field. When an electric current is passed through it, a magnetic field is created. This magnetic field helps to store the electric current for a short time, even if the supply is removed. When the magnetic field around the coil collapses, the electric current also falls off. Actually, the inductor basics are based on the Faradays Laws of Induction.

Inductor Symbol

The value of an Inductor is called Inductance and is measured in Henries. It is actually the SI unit of Inductance.

1 Henry = 1 Weber/ 1 Ampere

Working...

The working of an inductor can be further explained with the help of an example.

Simple Inductor Circuit

Consider a basic circuit consisting of a battery and a bulb. For this connection, there are only two outputs.  One is the bulb glow when the battery is connected and the other is the bulb off position when the connection is terminated. The circuit is shown below.

Simple light bulb

Now consider the same circuit with a coil of wire around the iron bar and the ends of the coil given across the bulb. Also connect a switch as shown in the diagram below.

inductor with battery light bulb

When the switch is closed, instead of the bulb to glow as a normal dim light, it makes a transition from bright to dim. As soon as the switch is opened the bulb makes a transition from very bright to off. As you can see, this is very different from the earlier explained connection. This strange behaviour is because of the inductor. When the switch is closed, the current starts flowing from the battery to the coil....