4 ms·
It's a gray market. Sometimes, I mean sometimes, these chips are real and they usually come from a "leak" in the supply chain - unauthorized resales by small ve
by segfaultbuserr 6y ago
It's a gray market. Sometimes, I mean sometimes, these chips are real and they usually come from a "leak" in the supply chain - unauthorized resales by small vendors, or "unwanted" surplus from a previous order or production run. Usually they exist only in small quantities and are stored and handled in unknown conditions, it's not something you want to use in production. But it explains why the AliExpress vendors always have some components when major distributors are out of stock (e.g. You can do it too - just order all the remaining stock of a rare chip from Digikey and put them on eBay...)
For example, I heard that a common practice in Shenzhen is selling reels of genuine components, but the "lot number" (serial number) on the labels are removed, so the manufacturers cannot trace these unauthorized resales back to the source. Another example, in a personal hobby project I needed to use a specialized controller that is not available on the public market, but a AliExpress vendor has them, it's likely surplus from somewhere.
> I can see those chips available in their thousands on aliexpress and similar sites for 10x the price
The quantity is not always real, sometimes they just put a random number here. And even when it's accurate, the sales occur via various online and offline channels simultaneously.
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Disclaimer: It's extremely risky to order components from an unknown source, I do not endorse doing it. And my hypothesis on their origins is my speculation, so take a grain of salt.
- Badfood 6y agoRandom story... I bought some resistor kits from aliexpress. I noticed the few I used were super accurate. So I tested a bunch. They were all accurate to, not sure exactly but let's say 0.1% ish. I went and measured a bunch of 1% ones from digikey,and they were around 0.5 to 1%. I guess they were tight tolerance ones that made it into a ultra cheap smd kit.
- Scoundreller 6y agoI like to think we’ve gotten so good at making something as basic as a resistor that modern/established manufacturers are so consistent there practically is near-zero tolerance for error.
- segfaultbuserr 6y agoIt's what happens when you buy random components, occasionally you get lucky ;-) There's a saying I've heard before: How many 1% resistors can you find in a bag of 5% resistors? None. The 1% resistors were already sorted out and sold as such. I'm not sure how true it is, but if it's true, perhaps a bunch of higher-precision resistors somehow made their ways into a resistor kit not because of random chance, but because they were surplus...
- rcxdude 6y agoResistors are so dirt cheap nowadays it's not generally cost effective to make 1% resistors by selecting from a process which makes 5% ones. It's much cheaper to just tune the process so you always get 1% without needing to do the selection. And when you get to higher precisions you have a trimmable design where you adjust the resistance with a laser to get it in spec.