| General > General Technical Chat |
| i won't buy chinise parts from aliexpress or ebay |
| << < (3/22) > >> |
| NivagSwerdna:
FWIW I've bought lots of chips from China that do work... and some that don't. For NOS items you probably don't have much choice as to supplier. For any quantity or long term supply purchasing then you need to go to a proper supplier not swim with the sharks on ebay. |
| SilverSolder:
I have had bad/fake transistors from eBay, but most of the time they are good. If the price is low enough, I don't mind testing - for hobby purposes. Anything serious, and I would head for a serious supplier. |
| DBecker:
I was bitten badly back in the great power MOSFET shortage a decade ago with re-marked lower capability parts. I've also gotten obviously fake security transponders. Parts that are obsolete or in high demand are commonly counterfeit/re-marked. Cheap commodity components, or parts that went out of production in favor of a similar new part can be a great deal for a hobby project where you don't need a large or long-term supply. |
| janoc:
--- Quote from: tunk on February 11, 2020, 05:07:13 pm ---Not everyone have had the same bad experience: Andreas Spiess recently tested some transistors from AliExpress and found that all except one were within spec: --- End quote --- That's not quite true. They were good enough for his project, but a claim of a part "being within specs" (as in datasheet specs) is something very different. He didn't really test that - and I am prety sure some would have failed if he has pushed them to the actual published datasheet specs. The testing in that video is a good sanity check that you didn't get something wildly different or completely fake (like those Sparkfun "ATMegas") but it won't tell you if the part is really genuine and meets all its specs. That may or may not be important for you, it depends on your project. However, it is an important distinction to make or you will get a surprise that that MOSFET or a voltage regulator blew up at half of the rated current or that the opamp is 3x noisier and has 1/4 of the expected slew rate - all due to cheap lower spec parts being remarked and sold as higher spec ones and your circuit actually taking advantage of the published specifications. Recycled but original parts are not necessarily a problem if you know what you are buying (given that you are unlikely to find another source anyway) - but if someone is selling a part that is 20-30 years out of production and claims it is new, with recent date codes, then there is something fishy there ... |
| Marco:
--- Quote from: cmrincon on February 11, 2020, 09:21:30 am ---Yesterday i was learning about mosfets amps and i decided to use a few 2n7000 N-channel mosfet which i got from aliexpress time ago. --- End quote --- True 2n7000s are the most statically sensitive component a hobbyist will handle (but shouldn't). You can juggle PC memory made with the tiniest of modern processes without much fear, but look wrong at a 2n7000 and it's kaput. Breadboarding with them is silly, use parts with proper gate protection. PS. a lot of them have gate protection now regardless of the datasheet, but you might have some NOS of proper ones. |
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