| Electronics > Projects, Designs, and Technical Stuff |
| Aluminum Electrolytic Capacitor Short circuit failure and Infant mortality |
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| senso:
Print is much lower resolution, heat-shrink has a different texture and colour, font is different, positioning of text is different. No manufacturer would change a whole line to make crappier heatshrink and printing, so, you have bought 1000 fake caps, most likely rebadged xxuF at 16V. Measure the capacity of the still not failed ones.. |
| graybeard:
If you put a small constant current (say 100µA) on the caps they should ramp up in voltage until they breakdown. If they are from a reputable source that breakdown should occur at greater than twice the rated voltage, but usually less than 4x. If they are new and breakdown at less than 2x they are crap and the lot should be rejected. |
| Ashraf Almubarak:
--- Quote from: 3roomlab on December 12, 2019, 07:01:52 am --- --- Quote from: Ashraf Almubarak on December 09, 2019, 12:54:41 pm ---These photos of the same capacitor (presumably) One we purchased 2 years ago and the other one month ago. can you notice any notable difference? --- End quote --- id say the 2 are different maybe the unit on the R is fake? so whats the correct answer? Yes you are correct probably the one to the right is fake. I contacted my supplier and he didn't proof that they are purchased from Nichicon, he said he will need time. Mean while he will buy me 1000 pcs again from mouser. --- Quote from: Ashraf Almubarak on December 09, 2019, 02:08:09 pm ---I thought if I provide them with specific part no. I would guarantee the original one. And If I gave them generic values I will not get any good one. It worked the opposite to me. For sourcing the material. I don't how to do this by my self this time. We are new company in a country that is very new to electronics industry. I need to have a supplier to arrange the receiving of the parts and arrange with assembly factory. Any way thanks for your precious answer. --- End quote --- you say you gave a bom to a assembler? but how do they prove to you things are original? if you search for a video by bunnie huang on fake chips etc, even he as a professional builder, get cheated by authorized dealers. according to his statistical study on certain products, distributors in china could mix in 3% of fake chips intentionally with originals to sell in bulk. and this is authorized distributors, not those down at assembler levels. --- End quote --- |
| wraper:
--- Quote from: 3roomlab on December 12, 2019, 07:01:52 am ---id say the 2 are different maybe the unit on the R is fake? --- End quote --- Cap on the right looks exactly like genuine nichicon. Cap on the left have several dodgy things. |
| Ashraf Almubarak:
--- Quote from: graybeard on December 12, 2019, 05:07:05 am ---If you put a small constant current (say 100µA) on the caps they should ramp up in voltage until they breakdown. If they are from a reputable source that breakdown should occur at greater than twice the rated voltage, but usually less than 4x. If they are new and breakdown at less than 2x they are crap and the lot should be rejected. --- End quote --- It is interesting test to do. Do capacitors manufacturer perform this test? It is my first time to know about it. |
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