Inductive Coupling :-

          Inductive or Magnetic coupling works on the principle of electromagnetism. When a wire is placed close to a magnetic field, it generates a magnetic field in that wire. Transferring energy between wires through magnetic fields is inductive coupling. when two conductors are configured such that a change in current through one wire induces a voltage across the other wire by electromagnetic induction. Then, they are said to be Inductively or Magnetically Coupled. If a portion of the magnetic flux established by one circuit interlinks with the second circuit, then two circuits are coupled magnetically and the energy may be transferred from one circuit to another circuit. This energy transfer is performed by the transfer of the magnetic field which is common to both circuits. The electrical Transformer is the simplest wireless power transfer between two coils.

Basic Transformer Circuit :

          During mutual inductance at the transistor, the electrical energy generated by the DC source is converted to AC output and a magnetic field is created around the transmitter coil. The receiver coil intercepts some magnetic field generated by the transmitting coil and an alternating current is induced in it. The received AC power is rectified and filtered to produce DC output. In an inductive power system, the distance and the alignment of two coils play a key role in the power transfer efficiency. With a constant primary current, the output power is proportional to the square of the mutual inductance between two coils. In other words as the distance between the transmitter and the receiving coil begins to increase, the output power decreases i.e, the receiving coil loses more and more magnetic field lines generated by the magnetic field in the transmitter. This makes inductive coupling an inefficient way of wireless power transfer and also wastes a lot of electrically transmitted power. So, in conclusion, we can say inductive coupling can be useful in transmitting power wirelessly within millimeters or centimeters.

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