What is an Inductor and How Does it Work? A Detailed Guide

An electrical circuit is made up of many components. This all depends on what the circuit is expected to deliver. That is why you can get both passive and active components. Today, we want to focus on inductors, which are passive components, to see their importance, types, and applications in electronics. Let us learn more.

Inductors Explained – The basics how inductors work working principle

What is an Inductor?

An inductor is a passive electrical component that stores energy in a magnetic field whenever a current passes through it. Inductors consist of a core and a coil of wire. The wire is wound around the core, which is made of materials such as ferrite, iron, or air.

 

How Does an Inductor Work?

Now that you have a good understanding of what is an inductor, next is to see how it works. We know it stores electrical energy in a magnetic field when current passes through it. However, how does this work?

It all starts with a magnetic field creation. This is possible when electric current flows through the coil of wire. It leads to the generation of a magnetic field around the coil. This magnetic field is the one used for storing electrical energy but in the form of magnetic energy.

According to Lenz’s law, the inductor opposes the change in current, whether increase or decrease, by inducing voltage in the inductor to resist that change in current. So, in this case, the induced electromotive force or EMF opposes the current change.

The next time you see an inductor symbol, you will know how it works and how it can be used for various applications. These include driving motors, filtering out AC signals, and power conversion and storage.

 

Key Parameters of an Inductor

You may come across terms such as inductance, DCR, Q factor, and others while looking into what do inductors do and wonder what they mean. Below, we quickly look at some of the key parameters of an inductor so that you can better understand it.

Inductance (L)

Inductance is a key parameter of an inductor that represents its ability to store electrical energy in a magnetic field. It is measured in henries (H).

DC Resistance (DCR)

This is the resistance of the inductor’s wire. It leads to energy dissipation in the form of heat. A lower DCR is more desirable, leading to efficient operation, especially in power supplies.

Current Rating

This is the maximum current an inductor can handle without exceeding its internal temperature limits or end up causing magnetic saturation. Whenever this current rating is exceeded, it can lead to inductor damage.

Quality Factor (Q Factor)

It measures how well the inductor can store energy in the magnetic field before losing it as heat. We want an inductor with a high Q-factor, especially for high-frequency applications.

Self-Resonant Frequency (SRF)

This is the frequency at which the parasitic capacitance and inductance of the inductor resonate, leading to an impedance peak. When the inductor operates above the SRF, it can lead to some performance issues and sometimes damage.

Temperature Rating

This is the maximum temperature that the inductor can operate at without causing performance degradation or exceeding its current rating.

 

Functions of an Inductor

The functions of an inductor help us get a clear understanding of what does an inductor do in a circuit. Here is what to expect.

• Energy is stored as current passes through the inductor. If the current changes or is interrupted, this stored energy is released back into the circuit.
• Inductors can also regulate current, resisting sudden changes in current flow and helping maintain stable current levels.
• Combining inductors and capacitors also allows for the filtering and removing unwanted signals’ frequencies.
• Power supply applications could also use an inductor to smooth voltage fluctuations and prevent rapid changes in current. This should help maintain a steady flow of current.
• Inductors can also be used in transformers to transfer energy from one circuit to another. Also, they are instrumental in creating resonant circuits and oscillating at specific frequencies.

 

Types of Inductors

There are various types of inductors in the market, each with different applications. Expect them to be categorized mostly based on their construction. Here are several options for inductor types.

Air Core Inductor

For this type, it has no core material. They can be used for applications with high frequencies since they come with low losses and are less prone to saturation.

Iron-Core

Unlike the other type above, this one has a ferromagnetic core such as iron. This increases inductance which makes it suitable for applications that need high inductance and also operates well at lower frequencies.

Ferrite-Core

The ferrite cores are also used in inductors that operate at high frequencies. This is because they offer low losses and are resistant to saturation.

Powdered Iron-Core

If you want a compromise between high frequency and high inductance performance, get yourself this type.

Laminated Core

This is a good choice if you need to adjust the inductor’s magnetic properties, as it uses thin sheets of laminated steel.

Toroidal Core

The core of this inductor is usually shaped like a donut. It provides high inductance for each turn, so it is expected to be used in applications with low frequencies.

Ceramic Core

In this case, ceramic is the core material. Ceramic is a good material for handling high-frequency applications.

 

How to Pick the Right Inductor for a Circuit

When you see a symbol of an inductor in a circuit, you just know it was picked for a reason. If you want to do the same, here is how you would pick an inductor.

Inductance Value

The inductance of an inductor is vital for the circuit’s operation. Therefore, it is critical to choose the right inductance based on the circuit’s operating frequency and impedance needs.

Current Rating

This determines the maximum current through an inductor that will not lead to saturating or degrade performance. Depending on the circuit design, you need to stay lower than the current rating.

Frequency Range

You always have to look at the rated frequency range of operation. This is important as it will determine if the inductor is good enough to work in your circuit or if you need to get a different unit.

DC Resistance

Ideally, we want low DC resistance to help minimize energy losses. This one also improves efficiency, especially in the power circuits.

Physical Size

This is key in determining whether the inductor will fit in the allocated space. It can also determine the inductor’s mounting style so that you can choose the right design for your circuit.

Cost and Availability

You also have to consider the inductor’s availability and price. Maybe you need to change it. Will it be readily available? And what is the price? Comparing different brands helps you understand the various options available.

 

How to Troubleshoot Inductors

Sometimes, the inductor might not work as expected. It could use troubleshooting to understand what could be the issue. Here is how you can troubleshoot inductors.

• A multimeter test can be good to check if the inductor is working correctly. You can do a resistance check or continuity check to see its performance. During a resistance check, you want it to have low resistance. If it is a high or open circuit, then it means the inductor is blown.
• You can also use an LCR meter. It provides an accurate inductance measurement compared to the basic multimeter. This is the best choice for high-inductance applications.
• The other choice would be an oscilloscope. This is a good pick for testing the inductor by observing the waveforms. Check for abnormalities or distortions in the waveform, as it can indicate a problem with the inductor.
• An impedance analyzer is also key to find out theimpedance of an inductor based on the frequency. It is a good tool for understanding the inductor’s behavior across different frequencies.
• Thermal imaging is key to determining whether the inductor is overheating, which can lead to damage if left unresolved. A thermal imaging camera can identify hotspots on the inductor’s surface.

 

Inductors vs. Capacitor: Know the Difference

The main difference is how the two store energy. Inductors store the energy in a magnetic field, while capacitors store energy in an electric field between charged plates.

Both have reactance, but they are different. In inductors, you get inductive reactance, which increases with the frequency. As for capacitors, you get capacitive reactance that decreases with the frequency.

How about AC/DC behavior? In inductors, DC current passes easily but opposes AC, especially at higher frequencies. Capacitors are different as they block the DC more effectively but pass the AC more easily, especially at high frequencies.

Another difference is that capacitors will resist the changes in voltage while the inductors resist changes in current.

 

Conclusion

There are many types of inductors in the market. What is important is that you always pick the right one for the job. We have covered what is an inductor, which should help choose based on the circuit design. Also, several brand reviews should be reviewed to find out if it delivers the best quality for inductors. This is key in ensuring you get the best value for money. Still, use the inductors as expected to always get the best performance.