Ken Shirriff made an incredible job comparing a counterfeit iPad power adapter to a genuine one. The teardown revealed that most of the time, the counterfeit chargers are a 5 watt charger instead of a 10, are poorly constructed, and have major safety issues.
The chargers look identical to each other than small differences in text. For instance, the real charger says Designed by Apple in California and cost $19 at its Retail and Online stores, while the fake one does not and only cost a couple bucks on eBay.
"The build quality of the Apple charger is much higher. In the counterfeit charger, some components are visibly crooked or askew. While this doesn't affect the circuit electrically, it indicates a lack of care in construction."
"Flipping the boards over reveals that the circuitry of the genuine Apple charger is much more complex than the counterfeit. The Apple board is crammed with tiny surface-mounted components in every available spot. The counterfeit board has a lot of empty space, with just a few components. Note the reddish insulating tape in the lower center of the Apple board, another safety feature of the genuine charger."
For your own safety buy the original one to avoide accidents and even death in some situation. Don't risk your life for a couple of bucks.
