Aliexpress is quite a thing

I love eBay and Aliexpress. They are some of the best website for a cheapskate electronic hobbyist. Pretty much any device you can imagine is for sale at a fraction of what these sort of obscure things would cost if you could find them at all. Often these sources are the only way to get items at a cost that would fit in a hobbyist budget

Random 20 year out of production IC? Got it. Obscure piece of test equipment? Got it. Cool eval board / module for basically any type of sensor? Got it. Assortment of SMD resistors in a nice case? Got it. And all that for usually only a few dollars.

However caveat emptor is the rule of thumb. eBay sellers in North America and Europe are usually selling legit items, maybe used, often “untested as-is” from people listing estate sale items they don’t know anything about. But usually that is pretty safe as long as your read the description carefully. However most of the fun and ultra cheap items come from China. And that is a different story.

Nowadays it is unlikely you wont get an item that look like what is in the picture. But that is all you can trust.

If you are buying raw electrical parts like I do there are three options:

  1. Scam part
    1. This is a part that is just meant to rip you off. It is the right package, and (usually poorly) marked with the part number, but is not the part you paid for and it has no chance of working
    2. If you bought a “Scam” 555 timer it would be a DIP8 package and would have “555“ written on it, but it would not contain the circuitry of a 555, it might be a remarked op amp, factory defects or empty packages (no die in the IC).
    3. Many people won’t bother to complain due to the low cost, wait longer that the purchase protection window to use the parts, or think they damaged the parts themselves, that is how these seller make money.
  2. Counterfeit part
    1. Also not what you wanted to pay for, but it might work. I consider these distinct from “Scams” in that it might work. They are pin compatible knock offs of branded parts, or similar cheaper parts that have been mislabeled.
    2. If you bought a TI op-amp, it might be a pin compatible cheaper op amp with the marking faked or an op-amp made by another company meant to be equivalent to the TI part. If you are lucky it might be good enough, if not it can waste a lot of debug time.
    3. Most power transistors are in this category, they are almost invariably lower power transistors marked is being rated for much more current
  3. Used part
    1. These are real parts salvaged from E-waste, and cleaned up to look new and usually with faked date codes to make everything look like it is from the same lot. There is a thriving market for these parts, and this does not just apply to high end parts. Somehow it is cost-effective to salvage ICs that cost 10s of cents. Labor is cheap I suppose.
    2. As much as I don’t like to support these sellers since they are lying about the product (claiming it is new) and supporting poor labor and environmental practices usually these parts work fine and for a hobbyist they are good. Better to reuse parts rather treating useful parts as scrap metal, but lying about the state of the items is wrong.
    3. These seller are a major issue for actual factory production. These parts have been found in medical and aviation supply chains and can be hard to tell from real parts, but may be out of spec have shorter lifespans due to age or mishandling during recycling
    4. I have seen sellers being honest about selling salvaged parts in a few cases and prefer to buy from them if possible, but they are a small minority
  4. Real part
    1. For something generic like an unbranded 5% resistor you will probably get what you pay for
    2. I am sure a few sellers are selling real ICs, but they are drowned out in sea of the other options

    For items other than parts these Chinese sellers can be quite good. Small electronic modules usually work as intended. I have never had an issue with knock off Arduinos, even if the IC is probably fake. Bulk packs of pin header and screw terminal are perfectly fine. Breadboard, jumper wires, etc are all likely to be of OK quality.

    Any numeric spec should always be taken with a grain of salt. LEDs are often listed with ridiculous power rating, batteries have a ‘0' tacked on the capacity. You need to know what you are buying, too good to be true items abound and are never real.

    I have found the more niche the item the better. With items in high demand there are often cheap, very low quality items produced for export only. With something a bit more obscure sometimes the China domestic version ends up for sale. These items I have found to be of pretty good quality.

    Overall I like these websites, as much as it is a “wild west” of questionable products it puts stuff into the hands of the hobbyist that would otherwise never be available. Don’t buy anything that is too good to be true, or is likely to cause harm if it fails at random, but do have fun looking for a deal on something neat.