The principle of wireless charging is to use electromagnetic wave induction. The process is similar to the power transformer. There is a coil at the sending and receiving end. The sending end coil connects wired power to generate electromagnetic signal and receives the electromagnetic signal from the end loop to induce the current to charge the battery. The principle of wireless charging technology can be traced back to 1830s. Michael Faraday, the scientist, first discovered the principle of electromagnetic induction, that changes in the surrounding magnetic field will cause electric current in the wire. By 1890s, an assistant to the Edison spectral radiant energy research project, and later scientist Nicola Tesla confirmed the possibility of radio transmission.