Below is a list of Toroidal Coils manufacturers from Polo, Illinois. Toroidal coils are electrical components that consist of a doughnut-shaped metallic core that has a conducting metal wire looped or coiled around it in order to form an inductor. An inductor stores electrical energy through the production of a magnetic field and introduces that stored energy flow into the metallic core. The most common material used to form conductive metal wire is copper, while the metallic core is typically manufactured using materials such as solid iron, solid steel or powdered iron due to their ferromagnetic capabilities.