Apple's little, white, rounded rectangle of a wall charger, the one all of us got with our iPhones, may look simple from the outside but internally, it's a lot more advanced than most cell phone or electronics chargers on the market. Ken Shirriff managed to disassemble one and found that there's a lot more than meets the eye.
The iPhone power adapter is a switching power supply, where the input power is switched on and off about 70,000 times a second in order to get the exact output voltage required. Because of their design, switching power supplies are generally compact and efficient and generate little waste heat compared to simpler linear power supplies.
The internals consist of transistors, resistors, diodes, and tons of other little parts paired with two circuit boards that work together to carefully regulate what kind of power is being output via your USB cord. Ken goes on to explain that even though these are quite a bit more advanced than simliar chargers by manufacturers like Samsung, Apple still makes one heck of a profit on them.
I was surprised to realize how enormous Apple's profit margins must be on these chargers. These chargers sell for about $30 (if not counterfeit), but that must be almost all profit. Samsung sells a very similar cube charger for about $6-$10, which I also disassembled (and will write up details later). The Apple charger is higher quality and I estimate has about a dollar's worth of additional components inside. But it sells for $20 more.
Apple issued a recall back in 2008 concerning the wall block and its ability for a prong to come loose and become lodged into a wall outlet accidentally. Tearing an older version apart next to a new one revealed that there were significant design changes made. Apple didn't go for a quick fix to secure the prong but completely redesigned the wall block altogether. This is a great example of how Apple still manages to focus on the little things, even if you can't see them.
Source: Ken Shirriff