how to transmit power(current) with out connecting wire(wireless power transmission)?

kelseymh6 years ago
Small to moderate amounts of power can be transferred wirelessly by coupled magnetic fields, the same way any transformer works. Many wireless power schemes try to make their system sound like something they are not,
with lots of odd terminology and dubious analogies, but ultimately they are just transformers.

A big difference between these systems and a regular transformer
is that with the wireless power system, the primary and secondary coils are not always in the same orientation, and the coupling between the two coils is not always constant.

These systems are all fairly short range, and can generally only work effectively over a range of several inches. This range can be imporoved somewhat when the receive coil circuit resonates with the frequency of the magnetic field from the transmit coil.

There is an organization working to set standsards for wireless power transfer and charging products, like cell phone chargers, etc. They have some good engineering information of the therory behind wireless power transfer.