woelen
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Fake/counterfeit electronic components
Up until now I had quite good experiences with buying electronics stuff from eBay, from chinese sellers, but now I ran into counterfeit electronic
components.
I purchased a set of 10 unijunction transistors (2N2646). I want to use them for experiments with negative dynamic resistance in non-linear circuits.
This is quite an interesting phenomenon and I wanted to dive deeper into that.
I found a nice-looking offer for 10 UJT's. Not really cheap, but affordable: http://www.ebay.nl/itm/161811179245?_trksid=p2060353.m2749.l...
I received the transistors quickly, but to my frustration, all of them are crap. These devices are totally useless, there is just some non-linear
resistive effect between any of the terminals, no UJT-behavior at all. Also, when I tried to find the correct pinout, I found that the legs of the
transistors are not aligned properly to the notch. According to all different datasheets on the 2N2646 I found that they are rotated 90 degrees
clockwise. These probably are some severely failed other type of transistor whose printing is removed and replaced by a 2N2646 print and sold as such.
UJTs are quite expensive and probably it is worth the effort to relabel off-spec crap.
The seller seems to be trustworthy though. We are working out a solution for this problem. I asked him to find genuine UJTs and if that fails, then I
get a refund. I think that indeed some sellers are victims and not really fraudulent. These sellers simply cannot check every single type of component
for validity, they have to trust their suppliers.
If we really cannot arrange anything, then I still have Paypal buyers protection for 90 days.
In the meantime I purchased three 2N2646 from another seller in Europe (Cyprus), which probably will be at my door in a few days, but which also are
almost three times as expensive as these chinese items, partly due to shipping costs.
I write this message as a warning to other people, tinkering with electronics. Counterfeit crap still is sold from China, although things are better
than let's say 3 to 4 years ago.
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Sulaiman
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You can simulate a ujt http://electronics.stackexchange.com/questions/28864/how-to-...
if you don't mind 100 V dc or thereabouts neon indicator lamps have a nice negative resistance region.
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Heavy Walter
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I had same odd experience buying through eBay a bunch of pendrives announced as "512GB USB 2.0 Flash Drive Memory Stick Thumb Storage U Disk Pendrive
Key Ring" but they doesn´t store any info!
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woelen
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I know of the neon lamps. I built quite a few relaxation oscillators with them, using a 150 VDC power supply.
The reason I wanted UJT's is that it is possible to combine them with other easy to obtain and cheap active circuit elements such as opamps. This
allows me to make more complicated circuits, possibly interesting chaotic oscillations and that kinds of things.
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Sulaiman
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Have you looked at multiple neons as a chaotic signal source ?
e.g. https://books.google.pl/books?id=buILBDre9S4C&pg=PA241&a...
also makes a nice novelty display 
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woelen
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Interesting book. I'll see if I can obtain a complete copy of that
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gdflp
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For woelen or anyone else who is interested in that book : http://www.sciencemadness.org/talk/viewthread.php?tid=4388&a... (Didn't want to put it in a public forum, so it's in References)
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XeonTheMGPony
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Cost comes from quality control.
Rule one if it is cheaper then normal there is all ways a reason!
rule two you get what ya pay for!
The golden rule if it sounds too good to be true it is because it most likely isn't! One thing I learned in electronics is never try or waste time
going for cheap as it literally will blow up in your face, and that smell sticks in a room a long time!!
As tempting as those deals are run! China can offer good deals on a great array of items but sadly they have a QC issue and a ferocious counterfeit
market in electronics atm So best to stick with the more expensive but reliable sources!
Sorry you got to discover it this way.
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Varmint
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I had an odd failure, my PC stopped communicating with the FTDI adaptor I use to communicate with my Pro-Mini Arduino. I assumed I wired something
wrong and either device was damaged, but after some detective work, it turned out to be a Windows driver.
Seems FTDI, the genuine vendor of the chip, discovered a way to detect Chinese clones, and provided a driver update via Windows Update.
Once installed, the driver checks to see if any connected chip is fake, and if so, "silently" fails to install. Meaning; no warning, it just stops
working.
Just for fun, I rolled back my system to the night before the "killer" driver, sure enough, the Pro-mini was able to communicate with the PC just
fine.
The laser markings on the top surface were "perfect" with a 10x loupe when compared to a genuine chip, so these cloners are getting serious.
After de-soldering, the country of origin info molded into the case proved to be from a region guaranteed by FTDI, ltd. to be bogus.
I started out mad at Microsoft for making it an "important windows update". In the end they were blameless, FTDI has every right to protect their
intellectual property, as does Microsoft.
I was mad at FTDI for disabling something I paid money for, I had no idea clones even existed of their chips. But, I have to respect intellectual
property, so they are free and clear.
I was mad at the store selling the product, but while researching the issue, I found plenty of people online with what turned out to be older versions
of the same product that had genuine FTDI chips on them. So, the guy at corporate signed a contract for off-shore supplied "USB to UART (FTDI)
adaptor", and thought little else about it.
So, its the store's supplier. Either they were guilty of neglect in product control, or they knowingly signed up with their chip supplier to use
clones.
I purchased a couple genuine chips from DigiKey, problem solved, lesson learned.
[Edited on 26-5-2016 by Varmint]
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Varmint
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http://www.techrepublic.com/article/ftdi-uses-windows-update...
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The Volatile Chemist
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The book Airframe, (by a perpetually recognized author...) talks about counterfeit plane parts. The idea of counterfeit parts hadn't occurred to me,
but I guess with the onset of Chinese manufacturing it became more commonplace...
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XeonTheMGPony
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http://newsfeed.time.com/2012/11/06/how-to-make-a-rotten-egg...
They even make fake eggs, if it can be counter fitted the chines have don it, My favorite is the counterfeit break pads made of ground up beans and
tea leaves
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mr.crow
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Quote: Originally posted by Varmint  | | In the end they were blameless, FTDI has every right to protect their intellectual property, as does Microsoft. |
Sure that is their right, but they exercised it in a negative and destructive way.
Initially their update would physically destroy the fake FTDI chips. I don't know if they changed it afterwards to just ignore it. https://www.youtube.com/watch?v=eU66as4Bbds
Would you want to live in a world where someone can come into your house and destroy something you paid for? This is inevitable with the increasingly
centralized and controlled Internet.
FTDI also doubled down on their intellectual property rhetoric saying it helps them innovate. Innovate what? They're making the exact same same chips
for over 10 years and they still cost $6 each. Just a cash cow.
The Chinese don't share our western concept of intellectual property so its not so black and white. They develop/clone their own technology to be
independent of outside influences. The USA already over extends their influence by bullying other countries to comply with their laws.
Sorry for arguing about nothing on the Internet, just some things to think about
Double, double toil and trouble; Fire burn, and caldron bubble
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Varmint
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Being an engineer, I take offense to "cash cow".
What in the world is wrong with getting $6 for something you invented?
Should they lay off a large portion of their employees?
Should they borrow money anytime they want to roll out a new product?
If they did, they could probably sell it cheap enough to ward off predation, at great expense to the company and it's communities.
If they had not bricked the chip in the one version, then anyone could go back to an older driver. But guess what? That driver is as much FTDI's IP
as the chip itself.
So, either they brick the chip, or anyone can continue to use old drivers, support piracy, and line the pockets of those who do business by deception.
So, I chose to focus the blame on the deceptive, rather than penalize someone protecting their IP.
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mr.crow
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I spent an hour typing rebuttals and thinking of counter rebuttals. Its was quite the argument. You make strong economic sense which is impossible to
counter with idealism. Engineers are known to be highly conservative.
Of course I would never use counterfeit part in a design. Or even a shitty quality capacitor to save a few cents.
I also value freedom. It was morally wrong to push an update that destroyed physical property to protect someone else's interests. It doesn't really
matter for a $2 serial dongle from China but is a symptom of a larger problem.
Computing and the Internet are becoming more centralized, controlled and censored. Freedom and innovation as we enjoy now cannot exist in this
environment. That's why Science Madness is an old-looking forum and not a Facebook page. Imagine telling your Facebook friends you mix chemicals
together for fun in your garage.
Double, double toil and trouble; Fire burn, and caldron bubble
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Harristotle
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FTDI
Sadly, FTDI were quite stupid on this.
Due to the contamination of the supply chain, a large number of their genuine customers were burnt on this.
I note that their share price was still less than half of its value over a year after that driver debacle, and they have never recovered.
Anyone into engineering medical or critical gear doesn't want to know them. Microsoft is angry that they updated their drivers, and, you know, those
alternative 340/341 chips are arguably better and certainly cheaper.
I guess it is a golden rule of business: try not to use you customers as ammunition in your trebuchet when you fight your rivals! You soon will find
that you no longer have customers!
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WGTR
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To address woelen's OP, I never buy electronic components directly from a Chinese seller. 90% of those are counterfeit. It's
actually more like 100%, but I'm trying to be generous. Shenzhen, China, is known as the counterfeit capital of the world around these parts.
Some parts are good counterfeits, other ones are bad. As more domestic processes get outsourced to China, sometimes an authorized manufacturer will
run an unauthorized extra shift (the "ghost shift"), and sell the excess out the back door, using possibly inferior materials, but with all the proper
labeling. If you buy from an authorized vender like Digikey, etc., or directly from the manufacturer, then you know that what you're getting is
legit, and will function as intended.
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woelen
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At least the seller from which I purchased the counterfeit 2N2646's refunded the money. I only had to ask once and I almost immediately received a
response from the seller that they will refund in a few days and indeed, two days later I had the money back on my Paypal account. So, I think that
the seller is a victim as well. The seller also removed the UJTs from his auction-list.
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XeonTheMGPony
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| Quote: Originally posted by woelen | | At least the seller from which I purchased the counterfeit 2N2646's refunded the money. I only had to ask once and I almost immediately received a
response from the seller that they will refund in a few days and indeed, two days later I had the money back on my Paypal account. So, I think that
the seller is a victim as well. The seller also removed the UJTs from his auction-list. |
That's the systemic problem, I rarely blame the sellers it is the manufacturers fault, not the company perhaps but corrupt elements from within the
company.
If I need it to work I order only from Canada or the US with registered certified parts, if it is a half assed personal project where I just want to
see if I can then perhaps I'll buy some parts from china, or from sellers that get certified parts, but all ways test them first befor putting them
near a circuit.
But the Chinese government has made some efforts of cleaning things up due to the multiple disasters there.
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woelen
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Thanks very much for the link. I am reading this book now and it REALLY is a nice book. It is easy to understand and brings interesting background
without becoming overly complex in mathematics. The book also gives quite a few ideas for experimenting yourself.
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