Abstract: We are implementing new concept in our project. We are going to transmit the electrical energy without wire. It is not easy concept. Here power is transmit from one place to another place using electromagnetic induction or laser concept. Wireless energy transfer or Wireless power is the transmission of electrical energy from a power source to an electrical load without interconnecting wires. Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous, or impossible. Wireless power differs from wireless telecommunications, where the signal-to-noise ratio (SNR) or the percentage of energy received becomes critical only if it is too low for the signal to be adequately recovered. With wireless power transmission, efficiency is the more important parameter. The most common form of wireless power transmission is carried out using inductive coupling followed by resonant inductive coupling. Other methods include microwaves and lasers.
1. Electromagnetic induction
Electromagnetic induction wireless transmission techniques are near field over distances comparable to a few times the diameter of the device or devices approaching one quarter of the wavelength used. Near field energy itself is non-radiative but some radiative losses do occur. In addition there are usually resistive losses. Energy transfer by induction is usually magnetic but capacitive coupling can also be achieved.
Electrodynamic induction method
Electromagnetic induction can work on the principal of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced in the secondary. Coupling must be tight in order to achieve high efficiency. As the distance from the primary is increased, more and more of the magnetic field misses the secondary. Even over a relatively short range the induction method is grossly inefficient, wasting much of