The phenomenon of a spark when unplugging a hair dryer is a manifestation of the fundamental principle of electromagnetic induction. When the current flows through the coils of wire in the hair dryer, it generates a magnetic field. The sudden interruption of this current, as the plug is pulled out, creates a rapid change in the magnetic field, inducing a voltage in the coil. This voltage can reach levels sufficient to ionize the air between the plug and the socket, resulting in a spark.
However, this same effect is leveraged in the design of chargers to convert high voltage mains electricity into smooth low voltage DC for devices such as phones and laptops. The principle involves switching the current on and off hundreds of thousands of times per second using transistors, creating pulses of electricity that need to be smoothed out.
Inductors, specifically designed to resist sudden changes in current, play a crucial role in this process. By storing energy in a magnetic field when the current rises and releasing it when the current falls, inductors help to convert choppy electrical pulses into steady DC. Nevertheless, the design of inductors is subject to a trade-off: the higher the voltage they must handle, the larger they need to be.
Anker's innovative approach to fast charger design, employing a technique called MBuck, has enabled the miniaturization of inductors. By splitting the conversion across multiple levels and switching at an astonishing 200,000 times per second, Anker has successfully reduced the size of inductors to a quarter of their standard size, allowing for the compact packaging of 160 watts of fast charging capability.
