Asking for help interpreting tolerance markings in capacitors.  - Page 1
Forum section: electronics / beginners

author: mistercris
author_rank: Contributor
timestamp: November 07, 2017, 05:36:41 pm
content: Short version:Trying to find if some caps I pulled off a board are ok to re-use. They are rubycon electrolytic caps.Specific example (one of them): 35v220uF YXA. BUT...my meter reads it as a 193uF.I'm assuming that (the YXA) is the tolerance but I cannot find ANYWHERE anything to confirm that and if it is what the values represent. Only other info on the thing is 3m1112 and 108C.The others have the (suspected) tolerance markings as YK or ZLHLonger version:Don't know how to use an iron very well so practicing by scavenging parts from trashed electronics. Figure if I cook parts here while learning I don't mind. I'm learning things like how to hold it properly. How important it is to keep the tip wetted and clean. How the temp fluctuates depending on how much crud is on the tip (that was a surprise actually) and also how hot the different pieces get while heating them. Bunch of things all at once all the while getting an in depth view of how "pros" attach the bits and pieces.Having said that, i'd like to use any parts that I can use (just to be thrifty). To that end, after pulling the part off I use my new meter to check the values against what's printed on the part to make sure it's still ok. So far so good, but I hit a bit of a wall with a bunch of capacitors I pulled off. The markings are way off what the meter is reading (I'm using the eevlog branded bryman). Unfortunately I can't tell if it's within spec or not cause I can't figure out the tolerance ratings on the things based on the markings I see. So either they're trashed or they're within tolerance. Can anyone help? Example above in the short version.

author: Audioguru
author_rank: Super Contributor
timestamp: November 07, 2017, 11:45:01 pm
content: An electrolytic capacitor has a very wide tolerance for its value of maybe -50% to +100% because it is usually simply used as a supply filter. You measured 193uF on a 220uF capacitor so its actual tolerance is (220-193)/220= -12.3% which is pretty good. It could be anywhere from 110uF to 440uF.A film or ceramic capacitor has a much lower value and is marked M for 20%, K for 10% and J for 5%.

author: mistercris
author_rank: Contributor
timestamp: November 08, 2017, 01:16:55 am
content: So I can keep them as "good" then?

author: retiredcaps
author_rank: Super Contributor
timestamp: November 08, 2017, 01:21:37 am
content: Quote from: mistercris on November 07, 2017, 05:36:41 pmYXA, YK and ZLH are the series. Rubycon makes many different types of caps for different applications. Some are general purpose, some are low ESR.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 08, 2017, 01:23:27 am
content: Even if the capacitance matches its sleeve rating that doesn't tell you if the cap's ESR is good or not. I have pulled many caps that have met their capacitance rating, but their ESR is 10x or greater than the specification sheet.The forums here have many discussions on sub $10 CDN ESR meters from ebay/china.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 08, 2017, 01:25:17 am
content: Dave's review.

author: retiredcaps
author_rank: Super Contributor
timestamp: November 08, 2017, 01:30:31 am
content: Quote from: mistercris on November 07, 2017, 05:36:41 pmIf you are going to desolder caps for re-use, I would only desolder the following brands: Rubycon, Nichicon, Panasonic and United Chemicon. The others aren't worth the time effort, solder and wear and tear on your tip.And yes, I have reused used caps in my own personal applications. I do use new caps on high profile or expensive electronics, but to save/recap a 17 inch LCD monitor with unknown ccfl hours left, I just use used caps.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 08, 2017, 08:43:33 am
content: Quote from: mistercris on November 07, 2017, 05:36:41 pmTry a different combination of keywords.https://www.google.com/search?q=yxa+rubyconLooks to be 20%. As others mentioned, its ESR may not be in spec -- now you also know the pass-fail band on that parameter, and can check it with an ESR meter!Tim

author: mistercris
author_rank: Contributor
timestamp: November 08, 2017, 01:38:09 pm
content: Dang it, that's the second time in two days I failed at google! Gotta get my game together. Thanks!Got a random esr meter on order. We'll see when it gets here.