I Bought Some JFETs on eBay - or Did I?

I have had some success buying low priced semiconductor components from China on eBay, including JFETs, until now...

Looking at forum posts going back years, several people have similar stories of their purchases seeming to be of fake components that don't have the correct specifications, have strange physical anomalies or markings from genuine parts, and in some cases the components appear to be a totally different type that's been re-labeled (eg: a JFET that tests as an NPN or PNP transistor).

The issue doesn't seem to be tied to any specific sellers - in fact one of the eBay sellers I had good luck buying transistors from, I saw forum posts from years ago saying that same seller had fake parts. I think it's just the nature of how these parts end up getting sold cheaply through these supply chain channels and you just have to be willing to gamble.

I did contact the eBay seller to report my findings and I received a full refund. Always purchase parts from a reliable source if they are for an important purpose.

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[chronobot]

Parts pirates need to walk the plank and drown in the briney deep !!!

[LimakZagan]

Fun note - real J201 will test as NPN transistor on these cheap-o testers due to very low Idss and Vgsoff. Keep in mind if you found this video while wondering why your J201 doesn't get detected as JFET.

[jamiesony]

I just found your channel and enjoying your videos. Good job.

I have been caught out with fake IRFZ44N mosfets from ebay. Destroyed loads of them, and a fair few driver ICs. It took me ages to work out that it wasn't my circuit at fault! (PWM motor controller) Finally worked it out when I salvaged some real ones from an old inverter and worked no problem.

[leachim]

I'm really happy you did a video on this. I had to figure this out myself the hard way when I got faked. I also bought them from a seller I had good experience with in the past (FSXSemi on aliexpress). Props to the seller though, they refunded me without question. I think JFETs are just one of those parts that are uncommon enough that there aren't very many floating around, unlike something like an IRFZ44n or 2n3904 which are cranked out in the bajillions.

[TheRadiogeek]

Relabeled parts. Wait till you get some relabeled tantalum caps. Boom! Never buy electronic parts on Ebay. Thanks for letting everyone know about fake parts. 👍

[henrikjensen]

I have gotten false parts on Ebay and Aliexpress a couple of times, both the FET that is a BJT and logic level power mos that are not logic level. Marking on the components is for the part I wanted.

[KenCostantino]

I have tested JFETs with the result of 2 diodes using a component tester similar to yours. I will use the multimeter method for confirmation.

[pileofstuff]

I guess I've managed to get lucky so far.

At least with components. I have received some power supplies that aren't exactly what was promised, though.

[TheEmbeddedHobbyist]

it's not just the usual eBay and Aliexpress sellers with fakes. I've seen x-rays of ic's from main stream distributors which look good on the outside but have nothing in side just legs and these were destined for the aircraft market. how they got into the food chain no one knows, but high value chips will attract the fakers.

[sanolivo]

Transistors are a big problem this days. Is a hit or miss. I purchased a pack of 1845 Fairchild transistors from Mouser. 3 out of 10 came in out defective. Making cracking noise.

[chronobot]

I had the same thing happen with a batch of mpf102s.

These could be useful if you wanted to make reverse engineering of your circuit more difficult.

[kokodin]

i have a batch of old polish made bf245 jfets and they are being very confusing to standard chinese component tester
it detect them one way as npn the but upside down they are detected corectly as jfets with very low current and source to ground voltage drop
i wonder what would component tester say upside down about those fakes

[alancooper]

Had the same this month. Actually bought batches from 2 suppliers on AliExpress, similar price, one lot were PNP transistors (also labelled BK15) the others look like good JFETS, labelled BA17, with a slightly different "F" logo. Instantly refunded for the fakes

[alvin]

Thank you. i do purchased those on e bay

[johnhousego]

Had the exact same experience few months ago complained to vendor and got refund but they never removed listing!

[RobertLongM]

Wish you added a perfect one ...
So in a basic Amplifier chip - would that work?

[sibsbubbles]

Risk for sure when you go "offshore" for part sourcing. There is only...maybe 1 seller I know of on the 'bay that has genuine stuff that isn't bs, or batch-failed/lower grade parts. Mainly from listings, and seeing original Phillips, ECG, RCA, etc. plastic bags from long ago was I able to feel confident that the guy had the real thing. Sucks that there is a market for this faking or poop quality rump-roast parts instead of good shit. Guess just when in doubt, try sticking to original as often as one can (however J201 I thought was nixed in TO-92 now).

[IPvFreely]

What values SHOULD you expect for a J201? I got some on eBay as well and want to confirm if they are legit.

[BryanDenham]

thank you for the video im just getting into building guitar pedals, i dont know much about the components yet, i think i got a bag of fake J201s . i ended up ordering a bunch of those SMDj201s and some adapter pcb boards to replace the fakes hoping i get real Jfets this time, also hope im able to solder those little SMD components in place, so small lol.

[charlesmatthias]

I buy from (Mouser.com) and so far I have received good (jfets')!
I have ordered (Jfets') from other suppliers' and they were either mixed, or all fake!
Usually an (NPN-transistor), pin-out (BCE), (hfe=150-200).It is a serious problem for builders' and repair people!
Best advice is to test everything with several different meters'!I use the Drok-meter and if I get (NPN, PNP),
then I test for pin-out and (hfe).Most fake-(jfets') are (BCE, NPNs').I think Mouser orders' their (jfets) from(Interfet), or other reliable manufacturers'.Only down-side, you will pay more, but in the long run will save a lot of