Coupling (electronics)

In electronics and telecommunication, coupling is the desirable or undesirable transfer of energy from one medium, such as a metallic wire or an optical fiber, to another medium.

Coupling is also the transfer of electrical energy from one circuit segment to another. For example, energy is transferred from a power source to an electrical load by means of conductive coupling, which may be either resistive or hard-wire.  An AC potential may be transferred from one circuit segment to another having a DC potential by use of a capacitor.  Electrical energy may be transferred from one circuit segment to another segment with different impedance by use of a transformer; this is known as impedance matching. These are examples of electrostatic and electrodynamic inductive coupling.

Types

Electrical conduction:

• Hard-wire conduction
• Resistive conduction
• Natural conductor

Electromagnetic induction:

• Electrodynamic induction — Commonly called inductive coupling, also magnetic coupling.
• Electrostatic induction — Commonly called capacitive coupling.
• Evanescent wave coupling

Electromagnetic radiation:

• Radio waves — Wireless telecommunications.
• Electromagnetic interference (EMI) — Sometimes called radio frequency interference (RFI), is unwanted coupling. Electromagnetic compatibility (EMC) requires techniques to avoid such unwanted coupling, such as electromagnetic shielding.
• Microwave power transmission

Other kinds of energy coupling:

• Acoustic coupler

See also

• Antenna noise temperature
• Coupling loss
• Aperture-to-medium coupling loss
• Coupling coefficient of resonators
• Directional coupler
• Equilibrium length
• Fiber-optic coupling
• Loading coil
• Shield
• List of electronics topics
• AC Coupling
• Impedance matching
• Impedance bridging
• Decoupling
• Cross-talk
• Wireless power transfer

References

 This article incorporates public domain material from the General Services Administration document: "Federal Standard 1037C". (in support of MIL-STD-188)