Electronic components power the world as we know it. Our lives revolve around technology, from large-scale international endeavors to the tiniest everyday gadgets. And at the heart of this remarkable technological symphony lies a handful of unassuming yet crucial components, from simple resistors to Integrated Circuits (ICs). In this blog, we will explore the role, function and production process of Fixed Inductors, one of the key components behind radios, televisions, power supplies, motors, and many other electronic devices.

What are inductors?

To understand fixed inductors, we must first understand the wider concept of inductors. Also called coils, chokes, or reactors, inductors are a form of passive electrical component with the ability to store electrical energy flowing through them into a magnetic field, and then convert it back into electrical energy when needed. This also allows them to control and manipulate electric signals, making them particularly important in AC circuits. Along with resistors and capacitors, inductors are one of the three kinds of passive linear circuit elements.

Inductors are necessary for allowing signals of certain frequencies to pass while blocking others. Chokes are a particular form of inductor used to block Alternative Current while allowing Direct Current to pass. This can be used, in collaboration with capacitors, to create tuned circuits, which are vital for radios and TVs. 

What are inductors made of?

The most fundamental component of an inductor is an insulated wire wound into a coil, frequently called a winding. It is the central element which allows it to generate a magnetic field. These are called wire-wound inductors. 

Other models use a similar principle without using wires. They are adequately called non-wire-wound inductors and include multilayer chip inductors and printed inductors. 

The capacity of an inductor to store electricity in the magnetic field is called inductance, and it depends on shape, materials used, environmental factors and other factors. According to the International System of Units, inductance is measured in henrys(H).

Depending on planned application and specific requirements, additional components can include: 

– A core, typically made of magnetic material, which enhances its magnetic properties, improving efficiency and performance by concentrating and directing the magnetic field.

– A shield, which provides protection from external magnetic interference, ensuring the inductor operates without disruption from surrounding magnetic fields.

– Packaging material, which encases the inductor and provides insulation, mechanical stability, and protection from environmental factors, such as moisture or physical damage. It helps maintain the integrity and longevity of the inductor within the overall electronic system.

Factors such as shape, materials used, and additional components can greatly influence the characteristics of the product.

What are fixed inductors?

Inductors can be classified into two categories based on their inductance. Fixed inductors, as the name suggests, have a specific and unchangeable inductance value. On the other hand, variable inductors can adjust and modify their inductance according to the requirements of the circuit or system.

Fixed inductors offer several advantages, including compact size, lightweight design, structural stability, ease of use, and convenient installation. They find their primary application in various circuits, serving purposes such as filtering, oscillation, trapping, and delay.

What do fixed inductors do?

When current passes through the coil of a fixed inductor, it creates a magnetic field on the right side of the current flowing direction. In contrast to a resistor, an inductor doesn’t convert electrical energy into heat but stores it in a magnetic field instead. Due to the fixed inductance value, we can easily predict the strength and effects of the resulting magnetic field.

When the flow of current in an inductor is stopped, the stored energy in the magnetic field returns back to the circuit – which is why fixed inductors act as a form of energy storage. They can also stabilize systems. For example, in an AC circuit, when an inductor is connected in series with an incandescent lamp and a switch, an interesting behavior can be observed. When the switch is closed, the lamp gradually brightens from a dark state, and when the switch is opened, it dims gradually before turning off completely. This showcases the inductor’s role in stabilizing the current by converting electric energy into magnetic energy and vice versa. The inductor ensures a smooth and controlled flow of current in the circuit, preventing sudden changes and maintaining stability.

The behavior of an inductor depends on the frequency of the electrical signals passing through it, and as previously mentioned this can be used to filter various signals or completely block AC currents.

Once the magnetic field in an inductor reaches its maximum capacity to store energy, it becomes saturated. If the current increases further, the strength of the magnetic field won’t increase, and any excess electrical energy will be released as heat, potentially leading to damage.

By having a constant inductance value, fixed inductors are easier to manufacture and useful for systems that are not too complex.

Example of a Fixed Inductor

The 74404043220A Fixed Inductor made by Wurth Electronics is a great example of a versatile component designed to meet the needs of various electronic applications. Part of the WE-LQS  series, this wirewound inductor features a ferrite core, ensuring reliable performance and efficient energy storage.

With an inductance value of 22µH and a current rating of 1.11A, the 74404043220A Fixed Inductor provides accurate and consistent performance, allowing for precise control and manipulation of electrical signals. It offers efficient energy storage, making it suitable for applications requiring stable power supply and voltage regulation.

The semi-shielded design of the 74404043220A Fixed Inductor enhances its ability to suppress electromagnetic interference, ensuring optimal signal quality and minimizing disruptions caused by external factors. This makes it an ideal choice for applications sensitive to noise and interference.

Operating within a wide temperature range of -40°C to 125°C, this Fixed Inductor exhibits excellent thermal stability, enabling reliable performance even in extreme environments. This makes it suitable for a diverse range of applications across various industries.

With compact dimensions of 4.00mm x 4.00mm, the 74404043220A Fixed Inductor offers easy integration into circuit designs, optimizing board space utilization without compromising performance. Its small footprint allows for flexibility in layout and facilitates efficient PCB design.

Count on Wurth Electronics for high-quality fixed inductors that deliver stability, precision, and reliability. The 74404043220A Fixed Inductor is built to meet the stringent standards of modern technology, ensuring exceptional performance in your electronic applications.


In this article, we have explored the role and functioning of fixed inductors, highlighting their significance in powering electronic devices and systems. At HEISENER, we take pride in supplying high-quality fixed inductors that meet the stringent standards of modern technology. Our reliable and efficient fixed inductors offer stable performance, compact designs, and precise inductance values, ensuring optimal functionality in a wide range of applications. With our commitment to excellence, we strive to contribute to the advancement of electronic technology by providing top-notch fixed inductors that empower the devices and systems shaping our world.