How Does The Inductor Work?

An inductor is nothing more than an insulated wire tightly wound around a magnetic core. The core can be a ferromagnetic material or plastic, or in some cases hollow (air). This relies on the principle that the magnetic flux develops around the current carrying conductor. If you know about capacitors, you will be familiar with the fact that capacitors store energy by storing equal and opposite charges in their plates. Similarly, an inductor stores energy in the form of a magnetic field that develops around it. Inductors respond differently to AC and DC. But before delving into "how inductors work." Let's look at its structure and characteristics.

Inductor structure:

Inductors are very simple to build from all the other components used in electronics. This is a guide to making a simple inductor. Only an insulating wire and a magnetic core material are needed to wrap the coil. A magnetic core is nothing more than a material that wires wrap around, as shown in the image above. There are different types of inductors depending on the core material used. Some common core materials used are iron, iron magnets, etc. In addition to the type of core material, it also comes in different sizes and shapes, including cylinder, rod, Torode and sheet. In contrast, there are inductors without any physical magnetic core. They are called hollow inductors or hollow inductors. The magnetic core plays an important role in changing the inductance of the inductor.

How does the inductor work

Let us begin by stating the fact that "magnetic flux will be produced on a current-carrying conductor." Similarly, when an electric current passes through an inductor, it creates a magnetic flux around it. In other words, the energy applied to the inductor is stored in the form of magnetic flux. The magnetic flux will develop in the opposite direction of the current flow. The inductor is therefore resistant to sudden changes in the current flowing through it. This ability of inductors is called inductance, and each inductor will have some inductance. This is given by the symbol L and in units of Henry.

The inductance of the inductor depends on the shape of the coil, the number of turns of the magnetic core winding, the area of the magnetic core and the permeability of the magnetic core material. The inductance of the inductor is given by the following formula

L = μN2A/L

L - Coil inductance

μ - Permeability of the core material

A - Coil area (m2)

N - Number of turns in a coil

l - Average length of coil (m)

Inductors in AC circuits:

As mentioned earlier, inductors act differently from AC than DC signal sources. When an AC signal is applied to an inductor, it creates a magnetic field that varies with time because the current that produces the magnetic field itself varies in time. According to Faraday's law, this phenomenon creates a self-inductive voltage on the inductor. The self-induced voltage is expressed by VL. In fact, the voltages generated at both ends of the inductor act in the opposite direction to the currents that resist them. The voltage at both ends of the inductor is given by the following formula

V L =L di / dt

VL - Self-induced voltage

di/dt - Change in current relative to time

If a current of 1 amp flows through a Henry inductor relative to 1 second, it will be generated on the inductor

"v. Now you can see how the current flowing through the inductor affects the voltage generated at both ends. The resulting voltage is the opposite of the current flowing through the inductor.

V-I characteristics of inductors:

Let's refer to the inductor's VI characteristic curve to better understand the above concepts. As a positive cycle of the AC signal passes through the inductor, the current increases. We know that the inductor hates changes in current, so it produces an induced voltage against the current that causes it. You can observe this at 0° in the figure above, where the induced voltage will be the maximum when the current starts to rise. Once the current reaches its maximum, the induced voltage becomes negative in an attempt to prevent the current from decreasing.

This cycle repeats, and from the figure above we can observe that the induced voltage generated in the inductor will act on the varying current flowing through it. Here, the voltage and current are said to be out of phase by 90°. Thus, through alternating current signals, the inductor stores and releases energy in the form of a magnetic field in a continuous cycle.

Inductors in a direct current circuit:

We now understand how inductors work with AC signal sources. Let's see how it reacts when used with a DC signal source. Recall that the formula for the induced voltage at both ends of the inductor is given by the following formula

V L =L di / dt

When using a DC signal source, the change in current relative to time will be zero, resulting in zero induced voltage at both ends of the inductor. Simply put, in a direct current circuit, the inductor behaves like a simple ordinary wire, and its wire generates some resistance. However, there is more when using an inductor with a DC signal source in a real circuit. In a real circuit, the current takes a very short time to reach its maximum from zero. At this moment, there will be an induced voltage at both ends of the inductor, which will be a negative maximum when the current begins to move from zero to its maximum. Once the current reaches a stable DC state, the induced voltage drops sharply to zero and becomes obsolete. When used with a DC signal source, the inductor will exhibit such short-span induced voltage spikes.

Inductive Reactance:

Another important thing to know about inductors is reactance. This is the resistance characteristic of components such as capacitors and inductors to AC electrical signals. The reactance shown by the inductor is called inductive reactance and is given by the formula

XL = 2πFL

From the formula it can be inferred that the reactance increases as the frequency of the AC signal increases, keeping in mind that the inductor hates changing currents, so it exhibits greater reactance to high frequency signals. When the frequency is near zero or the DC signal passes through, the reactance becomes zero, just like the conductor through which the input signal passes.