A device that includes a primary and a secondary coil is characteristic of which component used to induce current?

• A. Transformer
• B. Faradic coil
• C. Inductor
• D. Capacitor

Answer: (B)

Mutual induction between windings is what allows current to be induced in a secondary circuit. Energizing the primary coil creates a changing magnetic field that links to the secondary coil, producing current in that secondary path. In electrotherapy, the device that uses this two-coil setup to deliver current to the patient is called a Faradic coil. The primary coil connects to the power source, and the secondary coil, placed near the patient, carries the induced current into the tissue. This is the hallmark of the Faradic coil in clinical use: a coil pair designed to induce current in the body without a direct electrical connection. An inductor has a single coil and stores energy, a capacitor stores energy in an electric field, and a transformer is a general term for devices using two windings in power transfer—but the Faradic coil is the specific medical component that uses this two-coil induction to stimulate tissue.