Inductors, also known as coils or chokes, are passive electrical components that prevent sudden changes in current. At Custom Coils, we have been manufacturing high-quality inductor coils since 1978. We fulfill small and large volume orders and work with customers from design to product release to create superior products that meet your system needs.

What Are Inductors?

Inductors are electrical components that slow down current spikes or surges by using an electromagnetic field to temporarily store energy and then releasing back into the circuit. These components are used in electronic and electrical power devices for the following purposes:

  • Impedance matching
  • Creating LC circuits
  • Storing and transferring energy in power converters, including AC-DC or DC-DC
  • Blocking, choking, attenuating, or smoothing/filtering high-frequency noise in electrical circuits
  • Creating tuned oscillators

Inductors come in several types, categorized by form factor and construction principle, core type, or application.

Form factor and construction principle

There are lead type and surface mount device (SMD) types. Lead types include radial lead type and axial lead type. SMD types include thin film, multilayer, and wire-wound types.

Core type

When categorized by core type, inductors can either be air core or solid core types.


Depending on the application, inductors can either be fixed or variable. Fixed inductors are ideal for applications such as power supply circuits, decoupling circuits, general circuit applications, and high-frequency applications. Variable inductors are typically only used for high-frequency applications.

Benefits to Using Inductors

Inductors deliver several benefits to electrical circuits. They improve circuit performance by filtering noise, allowing circuits to operate without interference in small spaces with other electronics. Inductors also extend the life of the circuit and improve reliability by protecting it from surges and spikes in current.

Materials Used for Inductors

The type of inductor determines the materials used as well as the manufacturing method. Wire wound inductors rely on a core made of ferrite, non-magnetic plastic, or ceramic with a coil wound and soldered around it. Power supplies and general applications use ferrite, while radio-frequency applications rely on a non-magnetic material. Manufacturers machine a frame, mount the inductor to it, and coat the inductor in a molded resin. The frame forms the terminal electrodes.

Another category includes thin-film inductors much like semiconductors. They print thin-film coils onto a substrate made from magnetic metal, such as ferrite or alumina. The substrate is cut to meet the specified chip size, and the thin film inductor is formed by shaping and plating the terminal electrode.

Manufacturing layered inductors is possible using thick film printing or the more common sheet printing method. Sheet printing begins with preparing the multilayer sheets. Manufacturers fabricate a via hole and print an internal conductor pattern before forming the sheet layer. They cut and sinter the chip, then apply the terminal electrode and electroplate the inductor. Typically, ceramic is chosen for high-frequency applications, while general-purpose and power supply inductors use ferrite.

Inductors From Custom Coils

At Custom Coils, we manufacture inductors and chokes to suit a range of applications. We specialize in coils for high power and thermal applications and deliver prototypes and production runs in small to large volumes.

We design and manufacture several coil products, including air cores, bobbin wound cores, chokes, and inductors of various types and materials. Our products use 100% trackable parts and meet ISO, NEMA, and UL standards. We can also test for factors like surge and mechanical capabilities, and we offer a range of secondary manufacturing services.

Contact us to learn more about our custom inductor manufacturing capabilities or request a quote today.

Ready To Start Your Project?

The industry leader in custom design for magnetic coil applications for over 45 years.