Yesterday, Apple showed the world how courageous they are by abandoning their entire PC market. It’s not time for a eulogy quite yet, but needless to say, Apple hardware was great, and the charger was even better. It had Magsafe, and didn’t start fires. What more could you ask for?
When it comes to fake MacBook chargers, you can ask for a lot more. [Ken Shirriff] has torn apart a number of these chargers, and his investigations allowed for an obvious pun in this post. The fake ones will make sparks thanks to the cost-saving design, and shouldn’t be used by anyone.
A genuine Apple MacBook charger is a phenomenal piece of engineering, but the fake one is not. In fact, it’s almost the simplest possible AC to DC converter. The mains power comes in, it’s chopped up into pulses, and these pulses are turned into a high-current, low-voltage output in a flyback transformer. This output is converted into DC with a few diodes, filtered, and wired into a MagSafe adapter.
The genuine MacBook charger is much more complicated. Like the cheap copy, it’s a switching power supply, but has a few features that make it much better. The genuine charger does power factor correction, uses quality caps, has real isolation on the PCB, and uses a microcontroller that’s almost as powerful (and a direct architectural descendant) as the CPU in the original Macintosh. It’s this microcontroller that kept you safe that one time you decided to lick a Magsafe connector not allowing the full 20 Volts to go through until the connector has connected. Until then, the Magsafe connector only outputs 0.6 Volts. The fake charger doesn’t do this, and when you poke the connector with a paper clip, sparks fly.
This isn’t [Ken]’s first teardown of genuine and not Apple products. He’s done iPad chargers, iPhone chargers, and other small, square, white switching power supplies. The takeaway from these teardowns is that cheap chargers are a false economy, and you probably should pony up the cash for the real version.