#311 

I think I mentioned that in my video about transistors.

It is a good concept also for other areas...

I agree for special and more expensive parts. I only tested very cheap standard transistors where I even cannot believe there would be enough bad production runs. It could be that they are relabeled. In this case i think I would have discovered it.

@@AndreasSpiess Common way how fake parts are created is by relabeling a lower spec part as a more expensive higher spec one. Or a Chinese clone with slightly different specs gets relabeled/sold as the genuine part. Your test won't really catch that, only the gross fakes (a totally wrong part relabeled). This is common for both opamps, power transistors and even electrolytic capacitors. On the other hand, if your project isn't critical (most hobbyist stuff), it likely won't matter much as long as the part does what it is supposed to and you don't need the limit parameters (i.e. low noise precision/audio opamps, large current mosfets or power transistors for an amplifier/switching supply). For professional application (= something you are going to sell) you would be a fool to buy components from AliExpress or eBay, though. That said, even in Asia it is not a problem to buy genuine parts - e.g. LCSC or other reputable sellers will not sell you relabeled fakes.

Your theory is easily refuted. There is a large relabelling business in China. Often they just freshen up genuine salvaged parts to make them more presentable and easier to use in manufacturing, they straighten and refinish the legs, and they grind down the label side and repaint and relabel it. Obviously nobody will produce a new IC specifically for a fake, but for many categories of semiconductor products, you will find a lot of possible substitutes. 7406 is a generic part. Soviet Union started making one in the 70s designated K155LN3, and everyone else has one too, if Soviet Union had one, means China had one too going all the way back. There are literally dozens of different die designs (unlicensed) for the whole 40 and 74 series chips with same pinout and function, but different electrical spec. As far as MOSFETs go, you can do a quick check for gate capacitance, for fake ones it's usually not even in the same order of magnitude as the genuine part, so they have a completely different die design. Often enclosure differences are seen, and when they are decapped, a die of different (usually smaller) size is found inside. You will also find that whenever there is a REALLY popular part, whether Western or Japanese, you will find that someone spins up a part in China as a substitute to allow device manufacturers to reduce costs. I could give you a million example but i'll start with just one, the STM32F103 processor has been "cloned" by two different manufacturers, GigaDevice as GD32 series and CKS as CS32 series. They are not direct clones - they are compatible processors with same pinout, similar and largely compatible peripherals, and ARM licensed identical core, but they show behavioural differences and manufacturing process differences. So far so good, this is completely legal and valid. But then you'll find processors in the wild that are marked STM32 and vaguely made to look genuine, but are definitely not, and are instead actually these compatible replacements, see Alex Kenis for proof, and i think i might have one of those too in my pile of parts. And mind you, these CS32 and GD32 chips definitely cost a bloody FORTUNE to spin up, because they've got everything: high-density processor, flash, mixed-signal for comparators and ADCs, power semiconductors for the internal linear regulator, RC oscillators, they have just about every engineering complication you can think of, and yet it evidently made sense to build them. For some parts, it's certainly the case that there exists no fake die and every device is genuine, but often cosmetically manipulated. Some single devices are extremely likely to be fakes. The ratio of fakes varies depending on viability, and many reputable Aliexpress sellers are pretty good at dodging fakes for the most part.

I can explain how some of the genuine parts can be so cheap. Water absorption. SMD packages need to be dry for the soldering ovens or they can crack, so components have to be dry. They arrive sealed, but will start taking in moisture the moment they are opened. Depending on the component packaging (and climate) you could have from a day to a couple of weeks to use them. After that they're just no good for industrial soldering ovens. However, they're perfectly ok for hand soldering. They can be dried out, but it's usually just not worth it for the companies, so they go in the scrap bin (and get "recycled"). Skip diving and part recycling is an industry in itself in China. I would salute their green credentials if it wasn't done purely for money and their other industries weren't so polluting!

I would say inappropriate ESD + MSL precautions during handling, shipping and experimentation/installation is what creates a lot of issues. Want to pay for proper handling and care? - you do pay a higher initial price, and (hopefully) avoid a lot of issues and problems down the line if you do your part right. Want to gamble - buy from an unknown source, some are legit and honest - you (hopefully) win. Others aren't, and you (certainly) loose. This is my experience, not a theory.

It is also much faster with digikey (or similar). Even in Australia if I order a half reel of transistors it takes 4 days. My last order was made on a tuesday and delivered on the next monday.

Why would you buy single transistors? Buy a set of 25-50 of each for the $36-50 it costs and never worry about not having a fitting part. I only order from 4.8+ rating suppliers and have never had a serious problem. Any time something has been broken they refunded my money and let me keep the item. I paid 3.50 for 20 transistors from a store here and could have gotten 180 on aliexpress for the same price. For many products you can buy directly from the manufacturer on Aliexpress and save a lot of money. Voltcraft for instance sells rebaged Hantek stuff for crazy prices. My MSO5202 would have cost over 800 Euros and it sells for ~480 from Hantek. I paid 285 because I had ordered the DSO4102C but the seller sent me the more expensive one by mistake :D Banggood on the other hand is crap. The same Aliexpress products for more money and crap service. They cancelled my first payment and refused to give me the new member discount when I ran it again. Let me wait for 3 months to get part of my order and my multimeter had obviously been tossed around and was dirty. There were multiple items in the box and that was the only one covered in dirt and broken. Whoever packaged my order saw that it was dirty and put it in the box anyway and that is just unacceptable. Also the Microscope I ordered was listed as 3mp for $27 but was really a 1.2mp microscope that sells for $12.

Let's check what is "the little extra cost" :-D. I live in Canada, so I'm using CAD. Aliexpress: 100 of SI2301CDS cost 1.85 CAD + 1.39 CAD shipping. Digikey: 21.36 CAD + shipping. I didn't even bother to check shipping cost. So "the little extra cost" is >18.22 CAD. Maybe this is "little extra cost" for you. But for me electronics is a hobby and paying extra 600% (shipping not included) is way too much. The same story with Mouser.

If just one of the 0k1 transistors suffers from borderline behavior and forces you to spend two hours debugging on your hobby wage of as low as CAD $ 9 you already made up for that "reasonable extra". And don't forget the extra time disputing the seller. Additionally the professional suppliers handle their parts correctly. ESD-damaged parts mostly work but have a much lower life expectancy. When it comes to power transistors I'd consider the risk of fire too. DigiKey is expensive but not the only supplier. Here in Europe we have other distributors which are more economical at lower quantities. But yes, if all the factors add up "in phase" it can be worth the risk of course. Simultaneously I try not to forget that someone works for me a a wage which I don't like to work at. The prices that we pay in the western world better match the costs that we cause with our acquisitions - socially and ecologically: shipping just 100 transistors via airmail from the other end of the world isn't probably the most ecological mode of shopping. And counterfeiting isn't something that goes along with my ethical standards as well. But that's my personal opinion. We see: buying transistors isn't that easy :)

@@skeptical_bystander Exactly. If you buy quantity the prices do come down to the same levels though. Just small quantities make no sense. I have been trying to organize a giant group buy. If I could find 100 people to buy a full set of all resistors we could have 100 of each value for $5-6. The other option would be to make loot boxes. Each month you get a bunch of passives and a few transistors and connectors, some ICs, some consumables and 1 bigger item like a stepper or an ESP32 dev board. That would only make sense though with at least 1k orders a month guaranteed.

You are right. For bigger transistors I thought my crappy connectors and cables were enough. For smaller ones it would have been a good idea.

That is why I set the current first and raise the voltage after connecting the part. I did lose some LEDs until I noticed what is going on.

@@heyarno That is good enough for static parts like LEDs, where the voltage-current curve is constant and you only need to watch out when connecting the device. However for a FET it is different: you can connect it and then increase the voltage, however when you switch it on it will still draw much more current than the value set in the supply. (of course you can try to turn it on slowly so the peak will be less than when you suddenly switch it on)

@@heyarno this is always a good idea as well, because many of those cheaper power supplies with output filtering do tend to overshoot initially. So your solution is again a good idea for this test method.

@@Ormaaj Of course the preferable device for such measurements is an SMU (Source measuring unit). That is a power supply that is specified for usage as a voltage or current source in 4 quadrants, and also measurement of the resulting values. For "testing with what you happen to have available" a bench power supply and one or two DMMs is OK, but don't trust the capability of a bench powersupply as a current source... use a resistor to help it with that.

I still think the chance is smaller if you buy from a source with supplier check.

You are welcome!

^^^^ All very true. Exactly as I have discovered. You can get good products at great prices, but you have to do your homework and be a smart consumer. The Chinese aren't known for their honesty unfortunately.

Thank you for sharing your experience. I do not buy enough transistors to get a clear picture of who sells good quality and who not.

Thky hoy guys

yep, defective parts seem to be very common when buying on aliexpress. It's always extra work to check everything you get from them. For me it's still usually worth it though.

As mentioned in the video: I would not use these parts for production runs. As you mention: Too much work and risk.

When i order from Conrad or Reichelt i get a headache from their search engine :D You search for a specific thing and get thouseands of completely different parts as a result. TME is also a decent option for people that live in Europe or near Poland. Most parts i order from AliExpress or LCSC, if it's a more expensive thing or i need it quick i look at TME and the last option is Mouser where i always have a shopping cart that slowly fills up until i hit the limit of free shipping.

Not a "sensitive issue" merely facts. You get what you pay for.

Production surplus sounds like a good deal because it should be original parts.

I assume you used the proper method to compare the two. It is not easy to measure those small resistances.

Andreas Spiess at the milliohm range I suppose reading resistance with the four wire method is impossible due to active circuit. What would the correct method be? Maybe a low ohm shunt in series to measure the mV drop across it to calculate current, and we can measure the mV of Vdg. Impossible to have a precise current reading and it's not easy to find a high precision shunt, so I suppose a comparison between official and Suspicious parts could be the solution.

The shunt will not help you too much because you always need the voltage across the transistor if you want it’s resistance The comparison is always best.

Andreas Spiess but for a MOSFET the voltage can be measured, if we have the current reading through the shunt we know it's the same current through the MOSFET Drain to Source. So we have the I and V across to calculate Ron.

@@AndreasSpiess i was sceptic from the beginning and compared the device against one bought from digikey . i used a calibrated transistor tester. when i showed the evidence the seller he immeadetly returned the money.

Thank you for sharing your experience. I always file a well documented dispute if I am not happy with the quality.

Sometimes you are lucky and your transistor tester shows the defective or faked part. I very often use this device during my projects.

@@AndreasSpiess they now have capabilities to re-engineer and mass-produce MCU clones, add on top some competitive line on their datasheet and sell it for less. If you think that knockoff manufactures haven't stepped up their game too, you are in complete dark then. You have to be lucky nowadays to get a malfunctioning fake. Most of the times you get a QC discard or a remarked parts that work just fine, but are a lot inferior and cost pennies. They make it just as good, so that your time wasted on exposing them is not worth it. You can't be serious hoping to rely on a cheapo tester to back up numbers on a datasheet that you expect to use.

You are welcome!

You are right. I was too lazy :-(

@@AndreasSpiess I am lazy all the time - the difference is that I do not show my lazyness on youtube, because I am too lazy 😎

I would also assume it is more profitable to fake an expensive opamp than a cheap transistor. On the other hand I had never a faked MCU, which is also quite complex. But maybe easier to test.

This is strange. Usually, chips (exception: Opamps) seem to be ok.

You are right. It seems that the more expensive, special, or rare the parts, the more fraud.

So far I have very good experience with AliExpress. No problem with refunds if clearly documented.

Another Mini-360 victim. Welcome to the club ;-) As you pointed out, there are so many Mini-360 buck converters out there which are using the wrong inductor. In the meantime I avoid them, as you don't know what you get. MP2315 based buck converts are almost as small as Mini-360 and I had no issue with them so far. Unfortunately it's hard to find them when searching for MP2315 as they usually don't mention it. But they are offered as "Adjustable 1.8V 2.5V 3.3V 5V 9V 12V" and there is a soldering jumper for each of this fixed voltages and a potentiometer for adjustable voltage. The fixed voltage options are really cool as you can't change them by mistake.

Thank you for sharing your experience!

Thank yo ufor sharing your experience. It seems electronic parts from Chinese suppliers are generally ok because they are too cheap to fake...

I made a video about them. There you find the links.

TNX.

Bad luck. That is why I propose to do a quick test on arrival... Also because we would help AliWxpress to sort out the "cheaters"

Such a resistor would have helped, you are right. I cannot follwy your argument concerning 4:03

@@AndreasSpiess I'm not an expert, but you can extrapolate the other characteristics from the rise-time for those particular conditions, then change those times by altering the resistance and capacitance elements of the circuit to prevent ringing in your particular application. Changing local in-circuit values may shift the switching speed into an operational area where there is not a problem. (probably not a very good explanation, but I'm sure you get my drift)

Some commenters mentioned that it is not a good idea to buy rare transistors on Aliexpress because often, they are faked. Your way is much better. Especially giving feedback helps others!

Look at any video on youtube which shows how the electronics markets in Shenzen look like and you have the answer. Buying old, used equipment for manufacturing transistors or integrated circuits on 4-6 inch silicon wafers is increadibly cheap as the real factories upscale and renew their equipment all the time. Setting up a new factory is thus not difficult. If you then can produce transistors in TO220 packages which almost look genuine but use a much smaller die size, if you skip all steps of quality control and sell everything you produce you might be able to make a living of it - and then you will find it in China. With western cost of labor, premises and quality control this type of business would not be viable.

I would probably not buy products I depend on from unknown suppliers.

When repairing stuff, the question is always, why did it fail in the first place? So you can never be sure if your replacement parts are to blame or not.

In most languages your code, if it was valid, would always evaluate the first condition as true because its testing assignment and not equality.

😄

= = ==

donpalmera pseudocode?

@Tiago Ferreira Sounds legit to me , mine are about 4 years old from RS Components.

@Tiago Ferreira I bought some Hooyi MOSFET (HYzzz), waiting for their arrival, hope what i get matches the datasheet. I also looked at some NCEzzz part from Wuxi, they have some nice ones. How have your NCE hold up? Personally i think that is the "trick" to by on Aliexpress. Yes, some parts are plain fake (duds, esp. for long EOL parts, or a parts uplabeled, say 4A diode becomes 15A, normal OPAmp becomes high precision low noise), but thats IMHO a case of "you get what you pay for". A 35A Thyristor for under 10¢, sure... That doesn't even cover the cost for the silicon needed for 35A but sure... Where there is a margin for counterfeiting, there will be counterfeiting. But other parts are just second source/compatible. That used to be normal in the semi-industry, how many companies made a 555. Or the basic National OP-Amps LM339/LM358/LM393. And the list goes on and on with such "standard components". That has always been an entry point for small non-brand shops. First in Korea, then Taiwan. And now China. For Germans reading this: you guys clearly didn't order from Reichelt in the 80s and 90s ;-) Back then you would get mostly second source chips from them. And often a different every time. Remains of that can still be found sometimes in their order-numbers from when they slowly cleaned up their act. You can now order a "MJ 15016 ONS" (ON Semi/Motorola) or a "MJ 15016 ISC" (Inchange Semi). Back then you could just order a "MJ 15016", surprise what you would get (but never brands like TI/Mot/Philips/etc.) One can shout his anger in the wind getting a "fake" LM2575 (or other from the same family) or IRF. Or one can embrace it and buy the "copy"/similar from XLSemi, Wuxi or other never heard of companies in the first place. "Fit for purpose" At the moment i try to find these hidden gems of Chinese second source with the help of the JLCPCB parts list.

Voltlog did a video about that...

I always use the dispute process. I assume that they treat bad quality differently than lost packages. If I get bad products or damaged products it is important for me to give feedback. Also for the next buyer.

I have ordered a lot of products on Aliexpress and dispute process is far from perfect. For example I had the Aliexpress judge determine that I could only get a refund if I send back the defective item to china. And the postage would have cost more than the item was worth. Also if you want to contact Aliexpress there is no number that you can call. There isn't even an email address on the whole website from Aliexpress. So if you make your dispute too late then there's no way for you to talk to anybody. Moreover lately they changed the system so the order closes automatically after a certain time. Before you could "extend the time for the seller" and give the seller more time to still deliver the package without losing your ability to dispute. All in all I dread the system.

Ebay is 100 times better buyer protection wise and if everything else fails you can still talk to a human in ebay support. Aliexpress is not even close from a buyer safety persepective. I only use Aliexpress because I can't get some parts on Ebay and because of the price.

@@kwinzman I agree that ebay is much better, the problem is they often dont sell what I need, or are much more expensive. With aliexpress you always have to watch out for expiring buyer protection, check every order etc. I always contact the seller if a package has not arrived yet and tell the seller to extend the purchase protection (they can do that), or if it ends in just a few days, I additionally open a dispute and tell them I will close it if they extend the purchase protection. Aliexpress does have a live chat, but they have not been very helpful for me. So far the Aliexpress judges have been on my side when there was a problem, but yes, the system is far from good.

All (yes, ALL) my disputes with AliExpress vendors were about shipping. At some point in 2018 or so one of their usual shipping providers, Yanwen, seems to have gone rogue and just delivered about 80% of the ordered packages. And then there were the clear cheaters that just didn't post anything and gave you a non-working tracking code, or the ones that started a delivery but the shipping company never got the package. All of those were deemed as refund situations by AliExpress, so I can not complain at all.

I am never sure if it would be good for these people if I would stop to buy their work. Would they get better-paid work instead?

@@AndreasSpiess U wouldn't make the world a better place not buying stuff from China. But our industries+governments can make a change in China or India or Africa. And we are the ones that have at least some influence on what they do. It is an interesting fact that after 2000 when China opened a lil bit more to capitalism the amount of people that tried to escape to Japan decreased dramatically (in a good sense). For people interested I am not a good person to speak to but can forward you to lovely maker queen Naomi Wu. Please find her channel and let her know again that my gene-stealer agents are still out there and will get that little peace of DNA I need... OOOOPS got a lil bit off-topic now. Just me. And always listen to her talking mandarin... will give you a much broader + complete view of her than just her english version. It doesn't matter if you understand mandarin or not... so much information about her is transmitted in the way she is speaking her mother tongue. She is a true rebel and a punk and HOT beyond believe + always properly dressed.

I thought this is an international standard.

I think it has to do with your language rather than nationality. In german, and presumably swiss-german as well, U is the correct symbol. In english it seems to be V for voltage and volume.

Of course. But I did not plan to destroy the transistors ;-)

Andreas Spiess Haha, obviously not. My remark was aimed at those who haven’t yet tried it. 😉

Atellerul29 , Please explain how you would monitor this.

The difference can be everything.

@@BruceNitroxpro You can't really monitor it but you have two options: 1.build a test bench that simulates the wear at normal working conditions over a certain period of time or just compare it when let's say..you replaced a transistor in an amplifier which was never broken since 1985 and the replacement part only lasted 2 years...this is the long way but an obvious one so...it is not impossible to monitor it

@@Atelierul29 , Thank you. Excellent example! LOL

I think this is a good strategy. A good sleep is very important ;-)

I am no more active on HF.

Most of the power FETs are anyway too strong for my purposes and they never get even warm... So you are right.

Thank you for your detailed analysis. I agree, even if they are out of specs, they are usually usable for me.

Glad you like my style. I think we should always concentrate on what matters;-)

That one should be easy to detect, I think. But you are right. I read about them.

@@AndreasSpiess I fell for the low priced cards once, I can't believe that I thought I could get a card that sold locally for 39 bucks for 4 bucks on Ebay. But I did, still have them somewhere around my shop in a junk box I think with a big red X over them to show they are bad. I couldn't even get 4 gig out of the 32 gig cards.

@@JerryEricsson 32 were in reality gigabits. Divided by 8 makes 4GB. The seller used some wordplay. Common.

Your comment point in the same direction as many others: The more expensive and the rarer a part, the higher the chance for a fake.

So we are 2 ;-)

Andreas Spiess 3, I’m on board.

I'll 4th that, 7yrs of buying on alibaba/AliExpress, ebay bangood etc. worse I have had (eBay) was trying to get BME280 temp/press/humidity sensors, 4 different sellers all sent me BMP280 temp/pressure, all also gave me full refunds when I complained. O and often cheap batteries with 50% of stated capacity.

@Repairman diymore Alice 1101983 ic chip Store Super Mall of Electronic Components: are three recent ones.

@@Tocsin-Bang So these are reccomended sellers or not?

I made a video about the testers, but I like this one most

dave from eevblog reviewed it, these products are based on an open-source design where all the logic is located on a microcontroller, the only differences between these products are just some additional features.

take a look at the original project: ogy.de/l46k

:-)

Your choice. I have not big issues with AliExpress.

I would record the evidence with a video and file a dispute.

@@AndreasSpiess absolutely. Already done that couple hours ago so no answer yet. It was just a surprising find to be honest.

Me too. These cheap transistors are usually ok.

@@AndreasSpiess So I have the dispute resolution already. They have returned 3/4 of the price, but no information about the weird batch.

@Antonin Kral Here I am, sitting with a batch of 9J08AR P-Channel MOSFETS, and not only do they behave like N-Channel instead, but the Drain-Source connection is always open when reverse biased. In other words, they're faulty, throw them away.

You are right with the peak current. So far I do not have such applications in my lab because I buy my switching PS ready-made.

Indeed, standard parts usually are good. There is no reason to fake tehm because they are anyway cheap.

Thank you!

Thanks for your comment.

I agree that we have to pay attention. Particularly with rare or expensive parts sold cheap.

These transistors are defective or not FETs, or have a higher VGS that you applied. Even low quality FETS should have a lower ON resistance. I usually check the transistors when they arrive with my transistor tester that I can open a dispute if needed.

I agree, and if you read other comments, it seems that the more expensive the transistors are, the higher the chance that they are fake.

Thanks for sharing your experience. According many comments it seems that more expensive and rare parts are prone to faking.

Testing is always good. And sometimes even needed as your example shows. Other comments suggest that the more special and expensive a part is the bigger the chance for a fake.

You are right. Vgs influences Rds on.

A good decision. I was not so unlucky so far.

Thank you! I had a lot of luck in electronics!

Lead acid patteries are good for more than 160A. So your setup is ok. However, the 12 V bulb probalby does not need 160A ;-)

If they are labled as "unknown", nobody would probably complain, as in your case with your loca supplier. However, if they are sold as genuine and new and they are not, most of us would complain.

Thank you for sharing your experience! Particularly rare and expensive parts seem to be prone to counterfeit.

From the comments I learned that "standard" Chinese stuff often is ok. But the more expensive or rare a product is, the bigger the chance it is faked. For those I would go with a western distributor to be sure you are not cheated.

You are right. It is important to distinguish between bad chips and faked chips.

Btw, I forgot to mention, I usually buy on BangGood, and unfortunately, I did receive fake parts/equipment that is even dangerous like LiIon batteries, BMS'ses/loadbalancers etc... If something is really to good to be true, it usually isn't !

The new PS is on my bench and I like that I can key-in the desired voltage... I test most of the stuff I get. Especially batteries. And I file a dispute if they cheat.

You are right. Here, the problem with distributors are added cost for small orders and shipping cost. Usually prohibitive for makers.

Supercaps are sometime like those 8000mAh 18650 😂

@@AndreasSpiess Shipping cost are free when above ~30€, and so much faster! Something to think about. Yet, I'm still mainly buying in China.

@@wildinthejardin I finally bought a nice 2.5F supercap in a well known distributor. Impressive ... and still made in China ;)

I had exactly the same problem with supercaps. Perhaps it was the same dealer? Mine were these: www.aliexpress.com/item/32631591419.html?spm=a2g0s.issue_5ptha.0.0.278c4c4d5sRJOY

Looking at the various comments it seems, that rare and expensive parts are far more faked than the cheap and common parts I tested. What I also learned is, that you sometimes have to take your changes if you need an old part and gamble if you get a working one. Fortunately I am not in retro, so I do not have those problems.

Thank you for this tip!

Reading many comments it seems that you have to pay attention if buying expensive or rare parts. General purpose and cheap parts seem less faked.

Many commenters complained about fake rare or expensive parts. It seems that those are more faked than the cheap and common parts I tested here. Many modules are cheaper in China than in the West not only because of the bad quality, but also because low packaging and logistics cost and sometimes, no warranty.

You are right. I mentioned the story of the testers in my video about them ...

It is very good procedure to test your parts when they arrive and open a dispute if you feel cheated. Like that, we can prevent they cheat others.

Thank you for sharing your experience!

Unfortunately it is not about cents. Minimal order values and shipping fees add up to a lot of dollars. At least where I live.

I agree with your finding. The more expensive or rare, the bigger the chance for a fake.

JFETs seem to be faked a lot if I read the other comments

Thank you for sharing your experience!

It seems to depend on which transistors you buy. The more expensive/special, the higher the change for a Fake...

Many comments show some patterns, I think: The more expensive or rare transistors or even parts are, the more the change that they are faked. Here I tested common, cheap transistors. Maybe this is why I was a little more successful. I agree it is not easy these days as small manufacturers to make sure you get the right parts.

TO-3 cases seem to be faked more often if I believe the other viewers.

You can test it by applying the needed voltages and measure the currents according the data sheet (as I did). Or, maybe easier, you insert it into the place it belongs in your equipment and check it out.

AFAIK also reputable companies have their plants in China. This is not an issue for me. BTW: Most successful Swiss companies manufacture in China or in India these days.

You are right. But this is another story, I think. Much more professional than I am...

Thank you for sharing your experience. I am not sure if customer feedback helps a lot. Most of the comments I see are " I got it, it looks good, but I have to test it" ;.)

Thank you for sharing your experience

That is how I do it.

It is up to you. Here, low order value and shipping charges are not made for makers. They are much more expensive than some parts.

I do my tests and start a dispute if I am not satisfied. Better than comments, I think. Hurts more

I agree that unreliable suppliers are a pain in the a... Still, I get a lot of good things from Aliexpress. But I avoid some categories like specialized transistors. They are often faked, and it is hard to prove. Faked batteries are easy to prove and so far, I always got the money back. Cheap standard transistors usually are also ok because faking them is not rewarding.

You are right. Unfortunately it is not easy to distinguish between them after the sorting (if they are not labelled differently). But fortunately we usually do not use our parts to the limit and often can live with the 9th grade...

I do not know how the naming of a particular type is made. But up till now, I thought that the specifications should be very similar. Otherwise it makes no sense. I just lost a lot of time because my colleague ordered Atmega328PB instead of 328P. They are sold as compatible, but are not. For example the PB version does no more support an external crystal. So reading the datasheets thoroughly still seems to be important...

@@AndreasSpiess That is correct, but sadly less so these days of Chinese manufacturers. The 20V AO340x's are one such gotcha, as the CORRECT/ORIGINAL spec is 30V, let alone variations in rDS!

Did you watch this video? Or at least the summary before writing this comment?

As mentioned, the Chinese made cheap parts usually are not faked.

I agree. There is also a positive example: In his biography, Elon Musk "commanded" to use commercial grade chips instead of military grade chips for his rockets. Obviously it worked and he got it a lot cheaper. I think, the purpose dictates the selection of parts. For my prototypes I can live with dead on arrival parts. For an iPhone it would be ca catastrophy...