Inductive coupling

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In electronics, change in current flow through one device induces current flow in the other device. The two devices may be physically contained in a single unit, as in the primary and secondary sides of a transformer, or may be separated as in the antennas on a transmitter and a receiver. Coupling may be intentional or unintentional. Unintentional coupling is called cross-talk, and is a form of interference. Inductive coupling favors low frequency energy sources. High frequency energy sources generally use capacitive coupling.

An inductively coupled transponder comprises an electronic data carrying device, usually a single microchip, and a large coil that functions as an antenna. Inductively coupled transponders are almost always operated passively.

[edit] Implementations

Devices that use inductive coupling

• Transformer for AC power coupling and inductive charging
• Graphics tablet
• Radio Frequency Identification

A variety of inductive charging products charge batteries using inductive coupling, such as WiTricity.

[edit] Low frequency induction

Low frequency induction is an unwanted form of inductive coupling, which can occur when a metallic pipeline is installed parallel to a high-voltage power line. The pipeline, which is a conductor, and is insulated from the earth by its protective coating, can develop voltages which are hazardous to personnel operating valves or otherwise contacting the pipeline.