On Wed, 10 Dec 2008 23:05:25 -0800, DaveC wrote:

I need to buy some '3055's. Is there much risk of getting a counterfeit? I
read that because these are so cheap, they are being substituted (and
relabeled) for more expensive transistors. But there's not much profit in
counterfeiting 3055's.

Should I be concerned?

Thanks,

Yes. ALL components are being counterfeited in China nowadays.

And they are getting better at it by the day. I think they somehow get
into larger manufacturing plants. I have some microprocessors here
that were even lasermarked and were sent to me as free samples. They
(Chinese of course, who else) were probably hoping that we wouldn't
test them.

An example: Motorola. They sold the transistor division to ON
Semiconductor several years ago. And check ebay: new expensive
motorola transistors are offered there, they are ALL fake!

Sometimes there actually is a chip inside, but a small one. So it may
test ok but will be destroyed when you really when them to deliver
power.

Another thing the chinese do is taking out parts out of scrapped
equipment. They clean them, re-solderdip them etc. Often you can't see
it. But the parts are used. They may work, they may not.

And another thing they do is repacking parts that were rejected in
productionlines. Many parts ar made in Asia, the scrap is sent to
certain companies specialized in scrapping. But they just repack them
and sell them as new. Notice that these are rejected and potentially
(in medical equipment etc) dangerous parts!

And what they do too is remarking. They take normal processors and
make a military one of it by remarking them. On your testbench they
will test ok. But at for example extreme temperatures they will fail.
Would you like to be in an airplane controlled by such parts?

One of the causes is, just like with the crisis we have now, GREED.
Companies over here buy that scrap and sell it here to make large
profits. There are several companies in the US that cannot be trusted
anymore.

Stick with reliable ones like RS, Farnell, Mouser etc. That should be
safe.

P.