Its principle is the use of magnetic fields! Put into a similar transformer, a coil is transmitted, a coil is received, a capacitor is connected in parallel with the coil, so that the resonant frequency of the two coils is the same, the transmitter has an oscillator, the amplifying circuit, and the final switching circuit will be high The frequency of the pulse is applied to the transmitter coil. When the receiver coil approaches, it will induce a current, which is then sent to the battery via a rectifying filter circuit.

However, the efficiency is still not very good, can not reach 100%, the transmission distance is not far, generally does not exceed 25 cm, the farther the efficiency is lower, the efficiency may not exceed 50% at a distance of 5 cm.

Some people say that the charger's radiation is huge, this view is wrong, a charger's power is no more than 5W, but an electromagnetic oven has more than 2000 watts, plainly, the wireless charger launches with the principle of induction cooker Is the same, the radiation of the electromagnetic oven can heat the nearby metal to several hundred degrees, used for cooking, there is nothing!

In fact, such things as electromagnetic induction are very common in our lives, but we do not pay attention to it. For example, we are on the bus and the credit card machines used for credit card work are all based on this principle. There will be such a coil on the card machine to produce a High-frequency magnetic field, when our card is close, the coil inside will induce current, then this current is rectified and filtered and sent to the chip's power supply. The chip sends a signal to the card clock to complete a card-smoothing process. .