Incorrect values ​​in 0.1uf capacitor measurement - Page 1
Forum section: electronics / testgear

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 07:58:07 am
content: Why do I get such incorrect values ​​when measuring a 0.1uf capacitor?I tried with 7 different 0.1uf capacitors and always get absurd values.Some of the photos are crooked, I tried but couldn't fix them. Sorry.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: December 02, 2024, 08:16:43 am
content: Have you done a calibration of the unit with that test fixture ? you should do that first (will ask for a short and an open cal)

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 08:21:23 am
content: Yes, the calibration process was completed successfully every time.

author: Ice-Tea
author_rank: Super Contributor
timestamp: December 02, 2024, 08:31:47 am
content: Are you quite sure those are 0.1uF caps? Haven't seen all that many 100nF electolyte caps...

author: NE666
author_rank: Frequent Contributor
timestamp: December 02, 2024, 08:37:46 am
content: And to add what has been already asked r.e. their actual value, what is the source of these 7 'different' capacitors? That is to say, did you buy them together as a batch/bag from the same supplier? Or are these 7 fully independent data points? How old are they?Do you have any other meter you could use as a sanity check? e.g. multimeter with a capacitance range.What does your DE-5000 measure for other value capacitors you have to hand?

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 08:38:51 am
content: Of course I'm sure about what I'm measuring.That's another test.

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 08:49:21 am
content: Yes, they are all the same brand and were purchased from a single supplier. Do you think the 0.1uf capacitors are defective?

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 08:54:21 am
content: These are the measurements of the 0.22uF capacitor

author: NE666
author_rank: Frequent Contributor
timestamp: December 02, 2024, 08:59:05 am
content: Quote from: TA3UIS on December 02, 2024, 08:49:21 amAnd/or mis-labelled, yes. The probability of that being the case depends strongly on the manufacturer, the supplier and your source.If they are known brand, sourced from a reputable supplier (e.g. digikey, mouser, farnell, RS, etc. etc.) then it would be an odd thing. If they are from 'the internet', then very much more likely.

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 09:00:48 am
content: These are the 0.47uF capacitor measurements

author: NE666
author_rank: Frequent Contributor
timestamp: December 02, 2024, 09:04:56 am
content: Quote from: TA3UIS on December 02, 2024, 09:00:48 amWell, that suggests that your meters are in broad agreement, limited by their own resolution/accuracy/calibration/test freq.Hence, your "0.1" capacitors are almost certainly junk.

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 09:08:02 am
content: These are the 1uF capacitor measurements

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 09:13:16 am
content: I guess the 0.1uF ones are garbage as you said. Maybe the 0.22uF ones too?Here is another 0.1uF capacitor measurement from the same series.

author: Atlan
author_rank: Frequent Contributor
timestamp: December 02, 2024, 09:32:36 am
content: First, try to shape the capacitors a little under voltage, and discharge them before measuring. If it's the small low-profile capacitors, I don't use them as a rule, since they hit me with their leakage current. They don't even have vitality, who knows what - especially if it's not a well-known brand.

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 09:35:05 am
content: I will try this when I have time.

author: indman
author_rank: Super Contributor
timestamp: December 02, 2024, 12:01:03 pm
content: Quote from: TA3UIS on December 02, 2024, 08:49:21 amYes, these capacitors are of poor quality. Look at the pictures I took of similar specimens.In your photos, in addition to the wrong capacitance, these capacitors have a very high loss factor D, which is 10 times the same parameter of a serviceable one.

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 12:15:39 pm
content: The 0.1uf capacitors I have are also from the same brand. The ones I have are garbage...

author: SeanB
author_rank: Super Contributor
timestamp: December 02, 2024, 12:26:39 pm
content: Chengx, a clone of the Chongx capacitors, which are a poor clone of pretty much any other of a million other manufacturers. If you need to buy sub 1 uF capacitors do not ever buy electrolytics, instead buy polyester or polypropylene. Pretty much any film capacitor will be better in all respects other than size, and stay away from ceramic capacitors as well, unless you get NPO types, the standard and common X7R types have both a massive tolerance variation, plus also aregoing to change capacitance with voltage applied across them as well.But those ones apply close to rated voltage (you can put them all in parallel to do so) via a 10k resistor, so as to limit current, and also measure leakage, and leave them powered up for 48 hours to reform, and you will see a big change, though these cheap and nasty capacitors are best tossed and replaced with decent brand name types, like Nichicon, Vishay or Matsushita, though you will pay a premium for them, but they will last a long time in service, and have good performance.

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 12:47:47 pm
content: The ones I have are Cheng brand. I think they are the trash of trash

author: wraper
author_rank: Unknown
timestamp: December 02, 2024, 01:00:39 pm
content: Quote from: SeanB on December 02, 2024, 12:26:39 pmThe original is Chang (Changzhou Huawei Electronics, funded in 1987), the rest are knockoff brands of it. ChengX (Chengxing Electronic) eventually grew up into a quite large company (probably larger than Chang) with proper product range and datasheets, the rest are still one hung low shops, including Chongx. One on the photo is Cheng with no X.

author: indman
author_rank: Super Contributor
timestamp: December 02, 2024, 01:01:36 pm
content: Quote from: SeanB on December 02, 2024, 12:26:39 pmYes, it is better not to use capacitors from this company - there are too many defects and low quality products.

author: Aldo22
author_rank: Super Contributor
timestamp: December 02, 2024, 01:13:47 pm
content: I once bought some electrolytic capacitors in a big plastic bag from AE.They are certainly of cheap quality, but they are not as bad as yours.I have never seen so much deviation in new ones.In the attachment for comparison 0.22uF from my bag (my lowest value for electrolytic capacitors).

author: wraper
author_rank: Unknown
timestamp: December 02, 2024, 01:22:05 pm
content: Quote from: Aldo22 on December 02, 2024, 01:13:47 pmLtec is a decent Taiwanese manufacturer actually.

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 01:28:03 pm
content: The problem with Cheng or Cneng brand capacitors seems to be more common with the 0.1uF and a little bit with the 0.22uF capacities. Are they labeled incorrectly?

author: indman
author_rank: Super Contributor
timestamp: December 02, 2024, 02:00:27 pm
content: Quote from: TA3UIS on December 02, 2024, 01:28:03 pmIt's not a matter of labeling, read what I and others wrote to you before. Lots of fakes and defects!!!

author: TA3UIS
author_rank: Contributor
timestamp: December 02, 2024, 06:11:15 pm
content: It is necessary to stay away from these brands.