Phones, MP3 players, designer bags, artwork, money…. anything with value will bring out the counterfeiters looking to make a quick buck. Sometimes the product being counterfeited isn’t even necessarily expensive. For example, an Apple iPad Charger. [Ken Shirriff] got a hold of a counterfeit iPad Charger, took it apart, and did some testing.
So why would someone buy a counterfeit product? To save some money! The counterfeits are usually cheaper to reel the potential buyer in thinking they are getting a deal. In this case, the Apple product costs $19 and the knock-off is $3, that’s a huge difference.
A charger has one function; take household AC voltage and convert it to the 5v DC the device can use. Ken measured a few aspects of the electrical output of these two chargers. The left graph below is the Apple charger and the right is the counterfeit. The yellow lines show the voltage output. The Apple’s is narrow and flat and the counterfeit’s has a huge amount of noise. [Ken] actually had to change the scale on the ‘scope when measuring the counterfeit’s voltage so it is actually twice as bad as it looks visually. The orange lines show the frequency spectrum of the output. Lower is better. Overall, the counterfeit output is much higher with a consistent spike at the switching frequency.
[Ken's] article is extremely detailed and contains a lot of photos of inside both chargers so head over and check it out. You’ll be able to see where the knock-off cut corners to keep the price down. If you are interested in more counterfeit Apple chargers, check out the investigation that the Raspberry Pi Foundation did.