Air-Core Inductor, Iron-Core Inductor, Ferrite-Core Inductor, Variable Inductor

Toroidal Inductor

What is a Toroidal Inductor?

A toroidal core functions as an inductor, comprising two key components: a magnetic core and a coiled wire. When the wire is meticulously wound around the core, it generates a magnetic field that stores electric charge. In electronic circuits, the primary role of an inductor is to resist changes in the flow of current. Toroids come in various sizes and materials for their cores, and these variations influence their behavior across different frequencies. The way the coils are wound also plays a crucial role in determining the inductor's ability to store a magnetic charge. 

What Differentiates Toroidal Inductors from Other Inductors?

What separates toroidal inductors from other inductors is the shape. Compared to other inductors like ferrite or air core inductors, a toroidal inductor is shaped in a circle, like a doughnut. This closed loop shape allows for a wide frequency range. Also, it helps to minimize Electromagnetic Interference, due to the shape being able to concentrate the magnetic flux within the core. The core material is most commonly ferrite, iron, or metal.

closed loop toroidal inductor

Benefits of a Toroidal Inductor

Quality Advantage
High Inductance The shape of the toroidal inductor results in a higher inductance value. 
Wide Frequency Range A wide frequency range is important for proper signal transmission and reception, which can be useful in radio and communication systems.
Low EMI A low electromagnetic interference is beneficial due to its ability to maintain inductance ability and efficiency at low and high frequencies.
Compact Size The compact size allows the inductor to be used in applications where there a size constraints.


Toroids can be coated or uncoated, however coating a toroid with epoxy coating powder like the Linqsol GCP-1805 Halogen-Free Epoxy Coating Powder has many benefits, including:

  • Enhanced Insulation: Coating the toroid creates a superior insulation barrier between the magnetic core and the wire windings. This protective layer enhances the core's performance by reducing the occurrence of short circuits and electrical failures.
  • Corrosion Protection: As the core is typically made of metal, it is susceptible to corrosion. Epoxy coating powder acts as a protective shield, preventing moisture contact with the core, thus significantly lowering the risk of corrosion and potential failure.
  • Increased Durability: Epoxy coating powder provides essential protection to the magnetic core, creating a barrier between the copper wires and the core itself. This safeguard ensures the core's longevity while maintaining its intended functionality as a toroid.
  • Time Efficiency: In cases where toroids remain uncoated, additional materials such as tape are often employed to establish the necessary insulation barrier. Coating with epoxy powder eliminates this step, streamlining the manufacturing process and reducing production time.
  • Aesthetics: Occasionally, toroids may be placed in visible locations where they need to meet specific design standards. Epoxy coating powder offers the advantage of customization regarding color and provides a sleek, glossy, and uniform finish, enhancing their appearance.

powder coated toroidal core

Epoxy Coating Powder for Toroidal Inductors

Some key material properties of the Linqsol GCP-1805 - Halogen Free Epoxy Coating Powder:

  • Low-Temperature, Ultra-Fast Cure Speed: This coating cures rapidly at low temperatures, saving time and energy in the manufacturing process.
  • Low Shrinkage: The coating exhibits minimal shrinkage during curing, reducing stress on the toroid's core.
  • Low Moisture Absorption: Its low moisture absorption properties further decrease stress on the core and enhance overall performance.
  • Halogen-Free: The coating is free of halogen elements, making it environmentally friendly and safe for various applications.