[00:00] Have you ever noticed if you unplug an
[00:02] appliance while it's running like this
[00:04] hair dryer, then you get a spark? To
[00:07] make a 1 cm spark in air requires 10,000
[00:10] volts, but main's voltage is only around
[00:13] 120 to 240 volts. So, where is that
[00:16] extra voltage coming from? Thanks to
[00:18] Anker for sponsoring this video. When
[00:20] the haird dryer is on, current flows
[00:23] through these coils of wire, but that
[00:25] current also creates a magnetic field.
[00:27] And so when you pull out the plug, you
[00:29] are cutting off that current suddenly,
[00:31] which means the magnetic field will
[00:33] rapidly drop to zero. But nature hates a
[00:36] sudden change in magnetic field. So it
[00:38] tries to compensate. As the magnetic
[00:40] field drops, it induces a voltage in the
[00:42] coil to try to maintain that current.
[00:44] And that voltage can get so high it
[00:47] ionizes the air between the plug and the
[00:49] socket. That is the spark that we see.
[00:51] But this same effect can actually be
[00:53] quite useful because the purpose of a
[00:56] charger, a wall charger, is to take high
[00:58] voltage mains electricity and convert it
[01:01] into smooth low voltage DC for like your
[01:04] phone or your laptop. And to achieve
[01:05] that, the current in this device is
[01:07] switched on and off hundreds of
[01:09] thousands of times per second using
[01:10] transistors that creates all these
[01:12] little pulses of electricity. Now, to
[01:14] smooth those out, you require an
[01:15] inductor, a coil of wire just like in
[01:17] the hairdryer, just with a very specific
[01:19] design. Now this inductor resists sudden
[01:22] changes in current. It acts like a shock
[01:24] absorber. So when the current rises it
[01:26] stores energy in a magnetic field and
[01:28] then when the current falls it releases
[01:30] that energy again helping to turn choppy
[01:32] electrical pulses into steady DC. Now
[01:36] there is a trade-off which is the higher
[01:38] the voltage the inductor has to handle
[01:40] the bigger it needs to be which is why
[01:42] high power charges need really large
[01:44] inductors. But Anker has redesigned the
[01:47] circuitry in their fast chargers using a
[01:49] technique called embuck combined with
[01:51] their custombuilt algorithm. So instead
[01:54] of doing one large voltage drop across a
[01:56] single inductor, Embuk splits the
[01:58] conversion across multiple levels and
[02:00] switches it up to 200,000 times per
[02:02] second. That means the inductor has less
[02:05] energy to handle for every switch cycle.
[02:08] So the inductors can be shrunk to a
[02:10] quarter of the standard size. That is
[02:12] what allows Anker to pack 160 Ws of fast
[02:15] charging into a body this compact.