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i won't buy chinise parts from aliexpress or ebay

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Circlotron:

--- Quote from: vk6zgo on February 13, 2020, 02:32:34 am ---Meanwhile, half century old  CMOS gates have been working happily for, yes, half a century, in old equipment.
Perhaps the "ancients" knew something you don't! ;D

--- End quote ---
The good ones have certainly been going all that time.
The bad ones conked out and got replaced long ago.

DBecker:

--- Quote from: vk6zgo on February 13, 2020, 02:32:34 am ---Meanwhile, half century old  CMOS gates have been working happily for, yes, half a century, in old equipment.
Perhaps the "ancients" knew something you don't! ;D

--- End quote ---

No, the original MOS chips were as fragile as you have heard *as unmounted components*.  Once installed in the circuit they were much less likely to be destroyed.

Pretty much every part today has ESD diodes or similar protection.  Old CMOS didn't have the die area or process capability to do that.  Plus there was much more process variation between wafers, leading to some being especially vulnerable.  The especially weak ones died early, leaving only the robust ones.

jfiresto:

--- Quote from: DBecker on February 13, 2020, 04:34:27 pm ---... Pretty much every part today has ESD diodes or similar protection.  Old CMOS didn't have the die area or process capability to do that....

--- End quote ---
What sort of old CMOS do you have in mind? Even the original 4000A-series logic found room for ESD networks. Without them, the chips would have probably been too fragile.

Psi:

--- Quote from: wraper on February 11, 2020, 10:08:25 pm ---
--- Quote from: Psi on February 11, 2020, 09:55:21 pm ---The 2nd and 3rd price grouping is what you want to order. These will be good parts.

--- End quote ---
99% good is gross overestimation. Depending on what you buy they easily may be the same crap as the cheapest tier.

--- End quote ---

I'm only going on my experiences using aliexpress.
i've encountered more fake parts (that cause actual problems) from pcbway PCBA runs than from aliexpress.


The danger zone for fakes is parts that are specialized or a more expensive version of something common.
Like an extra stable voltage reg
or a low noise opamp
or a low rds mosfet
The most common fakes i've run across are where they take a similar but much cheaper chip and restamp it to be a more expensive version. These sort of fakes are not caught so quickly because the circuit still works most of the time.

TheDane:

--- Quote from: Psi on February 11, 2020, 09:55:21 pm ---The problem people run into with aliexpess is ordering by price and buying the cheapest option, because they are so used to doing that on other sites.

--- End quote ---
Having had only a few cases of issues vs. loads of great experiences I can add this to your excellent list:
Also:

Doing some research - take a VERY close look at the pictures posted and compare to what is in the datasheet or google pictures - and you can avoid wasting your money.

Buying from a seller which offers tons of other (non-related/electronics) stuff is also a potentially bad sign.
If they offer a wide variety of related goods, imho they also tend to be more serious and has 'better' parts in general.

Be kind, establish a long term relationship by re-ordering + don't bargain down the price - then ask the seller to look for component xyz at a trusted store/place.
Be a :horse:, dispute any little  :wtf: whilst only grapping the cheapest offerings - and you might make it onto a  :-- list (Many store names, fewer shops, couple of shippers, one receiver)

You get what you pay for, and you get treated as you treat others/'them'.
Be a sceptic and do your own pre-research. Sure it takes a bit longer to order and be kind - but it takes a lot longer for the order to arrive, even longer to re-order.

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