Fake or Counterfeit Electronics from China

[228238]

There are a lot of substandard electronics being sold on eBay imported from China ranging from semiconductors to modules.  Lately we have discovered semiconductors, usually MOSFET's that are fake / counterfeit.  They under perform and usually end up failing on the spot.  You can get a hint from the manufacture icon/logo stamp on the device.  Usually the logo is out of proportion, not as sharp, or missing.  Compare the logo with your originals. 

We have also discovered dozens of users selling fake dc power adapters.  Last couple days, we received an adapter rated at 12v 5a. However, on a bench check, at best, it could only produce up to 3 amps along with voltage degradation.  These are usually advertised as 2A 3A 5A 8A / 5V 12V  Power Supply Adapters For LED Strips.  We further found, by opening the case, someone is getting what appears to be 2a adapters, taking the electronics out of original case, adding an ac and dc connection, and then putting the modified electronics in a new case to advertise as 3a and 5a adapters.

[quackslikeaduck]

 I recently bought some MJ21194 and MJ21195 transistors from an eBay seller in China. None of these tested good, so I requested a return and got a quick refund. The seller did not request a return.

 A few years ago I had bought some MJE15032 and MJE15033 transistors, which tested good, but immediately went into thermal runaway when placed in service. I removed the plastic encapsulation from the failed transistors to expose the silicon, which was about 25% of what it should have been. Definitely Fake; I should have requested a return, but I had already given positive feedback.

 Over the years I've bought a lot of good items on eBay, and sold some. We should all take action to discourage selling defective and fake items. Best practice would be to withhold feedback, test product in-circuit and request return if defective.  By the way, real ON MJE15032 and MJE15033 will have a circular depression just above pin-3 in the encapsulation,.