Ferrite Toroids, or Ferrite Rings, are donut-shaped objects made from ferrite, an iron-based alloy commonly used in radio frequency applications. They are used for a wide variety of purposes, including shielding against electromagnetic interference (EMI) and for coupling different parts of an electrical circuit. Ferrite Toroids reduce the amount of EMI that passes through a circuit, isolating components on a board from one another. Additionally, they can be used as a transformer core, owing to their low loss in high-frequency applications. By wiring the different portions of the circuit to different sides of the ferrite ring, it can help maintain a consistent current throughout the entire circuit. Finally, they are used as an inductor, storing and releasing energy as an electromotive force in an electric circuit.