Defective components recieved

Dear Designers,
i received a defective component from LCSC from China.
It’s an inductor that was internally shorted.
This one:

How do you deal with defective components?

You will need to contact LCSC. They should be able to send you a replacement if it’s faulty.

LCSC is generally regarded as a reliable company.
There is always a chance something like that happens.
I would not worry too much about a single 3ct inductor.

By the way, how do you know that it is internally shorted? These inductors have pretty low DC resistance, hence you need to measure its inductance, too. Also your instruments (and probes) DC resistance would have an effect.

We are building a Switch Mode LED Driver in 1000pcs (Isolated Flyback Converter). And we measured the inductance to 800nH with an HP instrument.
I do not worry about the 3cts, I worry about my yield!
It’s not the 3ct, the driver has a manufacturing cost of 5 Euro.
Of course, I blacklist the manufacturer, But who knows, if the next one is not same as bad as this? Any experience how you handle this professionally? (We are a young startup)

You’ve done what’s needed. 800nH is pretty low.

Finding the sweet spot between the cost and quality is what we’re constantly searching :slight_smile: So we have some experience but still learning, too. If the inductor is not so expensive you can go with known manufacturers like TDK, Murata or Coilcraft. If the difference is big, then maybe you can buy bunch of them from Digikey and China and stress test them to find a viable solution, if you have time, of course.

My brother once bought a bunch of stuff from Mouser. A set of resistors had the wrong value, so he mailed them and mouser promptly replied that they would send new resistors, and they did. When the new resistors arrived, they also had the same wrong value as the first batch. So apparently they had a whole reel of them mislabeled or similar.

For him it was not such a big deal. I don’t think he complained a 2nd time but got the resistors from somewhere else instead.

Quite sloppy, but stuff like that happens.

Another example:
Some years ago I had a subscription on Circuitcellar (Electronic edition only) and some pages were missing. I mailed them, got an excuse and a few hours later a rivesed PDF, which indeed added the two missing pages I reported, but it still hade several other pages missing.

Blacklisting a reseller or manufacturer for a single faulty component is just silly. If it happens more often it’s time to get suspicious and put some effort into what is going on.

This forum is for Kicad related discussions. Calling out a company over one part is not the purpose of this forum. Defective parts happen. I know. I worked in repair most of my adult life. I’ve changed the title but won’t pull the thread at this point.


Yeah, I wondered about this one as well. There must be other forums that are better suited for moaning.

Like the actual distributor or original manufacturer :slight_smile:

Really comes down to what you expect from a part. If you are after a high degree of quality control you would choose and pay for a Q200 part. If not, such failures are inevitable

What is the meaning of 3ct?

From the link and the photo I wonder if you would be be better off spending more money on components and less on test equipment. The component specification seems to lack some fundamentals such as core saturation limit current and current limit for RMS heating. I have been designing power converters for 40 years and I have not heard of LCSC.

Yes I think all of these distributors now employ people who are ignorant. It is easy to find nonsense on the distributor websites nowadays. But I don’t remember the last time I saw a really defective part from Coilcraft or TDK or Murata.

I am locking this thread, it has nothing to do with KiCad at all