A power inductor is a solid state electronic component that receives and stores electrical energy utilizing a magnetic field. This field is typically created with tightly coiled conductive wire such as copper. Its principal use is to maintain a steady current within an electrical circuit with an inconsistent voltage and/or current. In most applications, inductors are matched with power capacitors which amplify or provide resistance to the applied or directed current. More than one power inductor can be used to create the power transformers that are utilized in electrical systems.
When energy is applied to the coil of a power inductor, it initially meets with resistance from the coil’s magnetic field. In an ideal scenario, this field then gradually allows the circuit to steadily receive full power from the power source. Real-world application inevitably leads to energy being resisted or dispersed throughout the circuit, which can be minimized and controlled depending on the type of power inductor utilized.
Each kind of power inductor is distinguished by the method in which the coils are wound and the presence and type of a central magnetic core. Air coils lack a magnetic core, but may still have a physical core made of a nonmagnetic material. These are designed for higher frequencies as they do not suffer “iron losses” which occur when high frequencies are applied to coils that do feature a magnetic core. They also do not see any variance in the levels of induction, regardless of the type of current used.
Coils with central magnets are termed ferromagnetic coils and can exceed the inductivity of air coils by over a thousand times due to the addition of the magnetic core material. Which material is used in these coils depends on the frequency of the current conducted by the coil. Laminated cores help prevent against energy lost as heat and are used in circuits with lower frequencies. When higher frequency currents are used, the core is comprised of nonconductive ferrite, which prevents loss of energy within the circuit due to hysteresis, magnetization of the core in one direction. The shapes of these cores also vary according to usage.
A hybridized version of these two, variable inductors, feature a core which can be inserted, adjusted to various depths, or altogether removed from a coil. The most common usage for variable inductors is the means by which one adjusts the received radio frequency in analog radios. Those and all other forms of power inductors are found on analog circuit boards.