Componenets from ebay, so cheap, is there a catch ?

I love the flash drive scams on e-bay, 64 gigs for $10. If its to good to be true than it may not be good.

Theres plenty of usefull suppliers I would consider long before ebay. Most people tend to go to factory first then franchise, and then the gray market which includes ebay

If you can test the parts after you buy them, its easy to buy from anyone. LED are simple, if they light, they work. But if you need them to be a specific wavelength or to have a particular lumens/watt, it may not be meet that spec. So in the end, as I wrote earlier, being able to test them for specific performance is your best guarantee whether you buy from authorized or unauthorized sources.

sasarchiver said:

i get most of my components from ebay. no catch. i get 100 RGB flashing leds for under £5 with free posting,or 100 3mm white/blue leds for £2.71 free p&p. but from hongkong so u wait abt 2-3weeeks but worth it. i have thousands of leds lol no hitches so far.

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LED are simple, if they light, they work.

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I have hard horror stories of people buying hundreds of LEDs for cheep to make arrays only to find out they all had different britnices.

You can buy 'grab bag' LEDs, usually they come to 1c-5c each in those bags, from various sources then use a light meter to sort them by lumens. This way you can have uniform brightness for a series of LEDs. If you need a specific wavelength you can also sort them with a wavelength meter. Often, these parts fail sampling QC at factories and the whole batch is discarded, but it also means many of them in that batch can be good. I wouldn't use them for devices you would sell to people, but good enough for home projects and fun gadgets.

4pyros said:

I have hard horror stories of people buying hundreds of LEDs for cheep to make arrays only to find out they all had different britnices.

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This happened to us. We built an architectural model of a skyscraper in Chicago, only to discover no two rooms had exactly the same brightness, OR COLOR. One was a little reddish, one was a little more blue. Found out after we had them all assembled in a three-foot model, of course.

Yeah the bulk bags of LEDs are suspected to be factory seconds, when they fail spec at the end of the production line they sell the dodgy LEDs in grab bags of 50 or 100 etc to hobbyists on ebay. The Vf spec will be all over the place, so brightnesses will be different.

I guess you'd have to test them, and maybe match them in groups for Vf or colour hue.

Mr RB said:

Yeah the bulk bags of LEDs are suspected to be factory seconds, when they fail spec at the end of the production line they sell the dodgy LEDs in grab bags of 50 or 100 etc to hobbyists on ebay. The Vf spec will be all over the place, so brightnesses will be different.

I guess you'd have to test them, and maybe match them in groups for Vf or colour hue.

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I recently bought a bag of 100 blue LEDs, and as far as I can tell so far, they all work great and are the same color and brightness. I am very pleased with this supplier. It just makes it even more difficult to know for sure if LED bags are factory seconds or if they're legit. It's just something that you need to decide for yourself--Is it worth the risk? I decided it was for me, because this bag of 100 LEDs was only $4. I figured if even ten of them worked, it'd be worth it

even on ebay, not all suppliers are bad. but in the example of 300 resistors for 1$, i fear the courier cost would fill another 5 $ make the cost miserable.
always better to order these components along with other parts to save on transport.

other day i bought 2 off ITE8512 from ebay and they were good enough.
likewise i bought a used ADSL modem on eaby.in and it is just fine.

but again too small purchases like single $ etc cost a moon on shipment cost.

DerStrom8 said:

I recently bought a bag of 100 blue LEDs, and as far as I can tell so far, they all work great and are the same color and brightness. I am very pleased with this supplier. It just makes it even more difficult to know for sure if LED bags are factory seconds or if they're legit. It's just something that you need to decide for yourself--Is it worth the risk? I decided it was for me, because this bag of 100 LEDs was only $4. I figured if even ten of them worked, it'd be worth it

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Good to know! Even with the factory seconds pretty much all of them will "work" but the brightnesses and Vfs will be quite different between LEDs.

Have you checked the Vfs of a few LEDs from the batch?

I got burnt with a 500 LED purchase from a reputable supplier (and not Ebay). I should have known that it was pretty cheap. The LEDs were all quite different in brightness and Vf and I had to hand match them, fortunately my Fluke meter has a Vf test that seemed to match them reasonably well.

To this day I don't know if they were actual rejects, or maybe just cheap because they had not been through the factory sorting procedure that puts them in batches of very similar Vfs. Or maybe shoddy manufacture standards where the process was too variable from part to part?

Normally if you get a 500 or 1000 quantity batch of LEDs from a good supplier the Vfs are very close, you can practically parallel the LEDs.

Wow, after reading some of these, I didn't actually realize how lucky I was to get a good deal.... I wonder if there's something I haven't seen yet. Maybe I should go through all of them one by one and test them with my DMM (has an LED tester on it)....

DerStrom8 said:

Wow, after reading some of these, I didn't actually realize how lucky I was to get a good deal.... I wonder if there's something I haven't seen yet. Maybe I should go through all of them one by one and test them with my DMM (has an LED tester on it)....

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You should do that before you leave feed back.

You don't need to test them all, but testing 10 will only take a minute and will give you a good idea if they are matched or not.

Mr RB said:

You don't need to test them all, but testing 10 will only take a minute and will give you a good idea if they are matched or not.

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I've tested 8 already (controlled by a port on a PIC) and was very pleased with the result.

I have bought many hundreds of led's of ebay and also some led digital meters used as volt and ammeters on dc battery chargers.
Have had no issues whatsoever.
Best thing is that shipping is free.
Normally postage is the biggest put off buying stuff on the web.

Best thing is that shipping is free.

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You have been lucky so far.
Shipping is not always free, In fact many sellers will over charge the shipping to try and make more money.

4pyros said:

You have been lucky so far.
Shipping is not always free, In fact many sellers will over charge the shipping to try and make more money.

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Yes, often the shipping is inflated and means they can sell the parts for nothing, and make profits from the shipping.

I ordered some parts from a supplier in Germany and they never turned up, i ordered some AC128's from another supplier and everything was good so i guess you take your chances with ebay, not saying the German supplier was bad though, anything could have happened after the order left Germany, mailing company could have lost it, customs could have siezed it, will never know.

Neil.

4pyros said:

I love the flash drive scams on e-bay, 64 gigs for $10. If its to good to be true than it may not be good.

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Hi,

Yeah and a friend of mine fell (64GB) for it and almost got burned but he used PayPal so it eventually got resolved to a refund. The big web catches lots of flies.

On the other hand, same friend also got a little meter for about 3 dollars normally would sell for over 20 dollars here in the US. We didnt check the accuracy but it wasnt made for super accuracy and we knew that already.

So in the end some fly and some get stuck in the giant web.

I buy a lot of stuff directly from china for resale... It is mostly good - the more complex an item, the more likely there is to be a problem. The pro's are obviously price, but the cons can be:
1) SLOW Shipping - It is free because it is slow. You think your PO (US, UK, EU) is slow, you have not dealt with the Chinese Post Office. It is not usual for stuff to sit for 1-2 weeks at the port of departure (even for "air mail") and the Chinese Post office shuts down a few times per year for major holidays (expect long delays for order from Nov to Feb), when ever there is any sort of major Communist Party party the post office slows to a crawl because of extra security.
2) you have to read the ads carefully, and check out any thing that is unclear before ordering.
3) Customs and Duty - in the US ICE is pretty lax / other countries they may hit you for a duty fees that can make a good deal into a dog.
4) Poor packaging - I have gotten orders of CMOS chips that where packed like this: Chips lose, wrapped in 3 layers of non-ESD bubble wrap, bubble wrap wrapped in shipping tape, labeled and shipped. Money saved = time wasted testing each chip, and straighten bent pins.
5) Cultural differences in standards of customer service.