Comments on: EEVblog #33 2of2 – Capacitor Tutorial (Ceramics and impedance) http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/ NO SCRIPT, NO FEAR, ALL OPINION - An off-the-cuff Video Blog for Electronics Engineers, Hobbyists, Hackers and Makers Thu, 09 Sep 2010 18:50:12 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Sean http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-2278 Sean Mon, 19 Oct 2009 05:30:53 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-2278 Tech application notes from Intersil on choosing bypass capacitors. http://www.intersil.com/data/an/an1325.pdf Pages 5 and 6 tie in with your whiteboard graph on using more than one capacitor. Tech application notes from Intersil on choosing bypass capacitors.

http://www.intersil.com/data/an/an1325.pdf

Pages 5 and 6 tie in with your whiteboard graph on using more than one capacitor.

]]> By: Sean http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-2277 Sean Mon, 19 Oct 2009 05:25:54 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-2277 The helical resonators in old GE mobile business radios tended to have a lot of problems with whiskers according to a radio tech friend. The helical resonators in old GE mobile business radios tended to have a lot of problems with whiskers according to a radio tech friend.

]]> By: nick http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-2247 nick Sat, 17 Oct 2009 20:11:30 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-2247 It says "ROM" See it fullsize: http://www.eevblog.com/favicon.ico ;) It says “ROM”

See it fullsize: http://www.eevblog.com/favicon.ico ;)

]]> By: Adam http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1915 Adam Mon, 05 Oct 2009 17:40:42 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1915 Wow! More like these please. Amazing. For newcomers like me to this, these brain dumps on basic components are very helpful. Wow! More like these please. Amazing. For newcomers like me to this, these brain dumps on basic components are very helpful.

]]> By: Mark http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1800 Mark Fri, 02 Oct 2009 02:17:36 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1800 Yes, I've heard it's a big problem above 3 GHz... not anything I've ever worked on. Yes, I’ve heard it’s a big problem above 3 GHz… not anything I’ve ever worked on.

]]> By: EEVblog http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1795 EEVblog Fri, 02 Oct 2009 01:01:19 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1795 Haven't run into the problem personally, but know of some who have. Usually it's one of the more obscure problems and not something your ordinarily worry about, but when it does happen the proverbial !@#$ can fit the fan! Haven't heard of the antenna aspect. Off the top of my head it would have to be incredibly high frequency to be an issue, given the typical lengths involved. Haven’t run into the problem personally, but know of some who have. Usually it’s one of the more obscure problems and not something your ordinarily worry about, but when it does happen the proverbial !@#$ can fit the fan!
Haven’t heard of the antenna aspect. Off the top of my head it would have to be incredibly high frequency to be an issue, given the typical lengths involved.

]]> By: Mark http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1788 Mark Thu, 01 Oct 2009 18:58:17 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1788 Dave, I had an idea for an interesting topic you could speak about in one of your segments... "tin whiskers". I find it interesting that such a small, little known problem can cause so much damage(tin whiskers were responsible for the failure of the Galaxy IV satellite). I hear they can cause lots of problems in high frequency circuits because they act like little antennas. Have you ever run into this problem? Thanks, Mark Dave,

I had an idea for an interesting topic you could speak about in one of your segments… “tin whiskers”. I find it interesting that such a small, little known problem can cause so much damage(tin whiskers were responsible for the failure of the Galaxy IV satellite). I hear they can cause lots of problems in high frequency circuits because they act like little antennas. Have you ever run into this problem?

Thanks,
Mark

]]> By: John McVirgo http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1787 John McVirgo Thu, 01 Oct 2009 13:36:26 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1787 Dave, a great blog that is very informative as usual. What has been the most difficult project you've been involved with that required the greatest level of technical know-how from you? Dave,

a great blog that is very informative as usual.

What has been the most difficult project you’ve been involved with that required the greatest level of technical know-how from you?

]]> By: Eldon Brown http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1778 Eldon Brown Thu, 01 Oct 2009 02:59:03 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1778 I like IT! . . . but I can't quite read the part id :-) I like IT! . . . but I can’t quite read the part id :-)

]]> By: admin http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1750 admin Wed, 30 Sep 2009 00:27:29 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1750 Done! I now have a favicon.ico to keep the geeks happy :-> Done!
I now have a favicon.ico to keep the geeks happy :->

]]> By: Mark http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1740 Mark Tue, 29 Sep 2009 16:27:32 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1740 Dear Dave, Your blog is wonderful. I'm learning so much from it. I get very excited about electronics and it's very hard to find other people who do as well. Keep it up! I eagerly look forward to every update. Thank you, Mark Dear Dave,

Your blog is wonderful. I’m learning so much from it. I get very excited about electronics and it’s very hard to find other people who do as well. Keep it up! I eagerly look forward to every update.

Thank you,
Mark

]]> By: Mark http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1739 Mark Tue, 29 Sep 2009 16:25:05 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1739 Brian, Thanks for the info! I'll keep this in mind. Mark Brian,

Thanks for the info! I’ll keep this in mind.

Mark

]]> By: admin http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1725 admin Mon, 28 Sep 2009 21:21:15 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1725 No, it's definitely static. I can get the same effect by rubbing my jumper on the chair (which does not produce noise or vibration). No, it’s definitely static. I can get the same effect by rubbing my jumper on the chair (which does not produce noise or vibration).

]]> By: James Lerch http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1716 James Lerch Mon, 28 Sep 2009 14:30:58 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1716 Hey Dave, Could this audio vibration effect of multilayer ceramic capacitors be what you saw back during your O-Scope mystery? You know, when you stood up quickly and the scope showed 140mhz signal? I wonder what the resonant frequency of a small smd cap is? Hey Dave,

Could this audio vibration effect of multilayer ceramic capacitors be what you saw back during your O-Scope mystery? You know, when you stood up quickly and the scope showed 140mhz signal?

I wonder what the resonant frequency of a small smd cap is?

]]> By: James Lerch http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1715 James Lerch Mon, 28 Sep 2009 14:16:36 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1715 Clearly it should be something like this, the Ohms law pie chart! :-) http://t1.gstatic.com/images?q=tbn:8Myl_CdugrPx7M:http://www.getahelmet.com/jeeps/tech/ohm/ohmslaw.gif Clearly it should be something like this, the Ohms law pie chart! :-)

http://t1.gstatic.com/images?q=tbn:8Myl_CdugrPx7M:http://www.getahelmet.com/jeeps/tech/ohm/ohmslaw.gif

]]> By: Brian Hoskins http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1696 Brian Hoskins Sun, 27 Sep 2009 17:14:25 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1696 One interesting (and in my opinion important) thing to mention about the class II ceramic capacitors (i.e. the multi layer ones) is the problem of "aging". I got caught out by this once, because an ICT system I designed was chucking out a high percentage of product due to some capacitor measurements coming in outside of specification. The capacitors were X7R devices, and removing them from the board and taking measurements confirmed that they were indeed outside of tolerance. That part of the story worked out fine, but I then decided to investigate the reels of components we have in stock and, to my astonishment, almost every single reel we had (I'm talking thousands of components here) seemed to read out of spec. Curiously, the measurements I made were always *below* the stated tolerance. My immediate reaction was to complain at the supplier, but a colleague pointed me in the direction of an article about the "Aging" effect on multi-layer ceramic caps. The aging effect, as I'm sure you're aware, causes the capacitance of the device to decrease with time. This effect can actually be reversed by raising the temperature of the device above a certain threshold (approx 150 deg c I think) and with this in mind it is expected that any SMT or hand soldering process would reset the aging effect and bring the capacitors back within specification. So, whilst we did indeed seem to have a tolerance issue with some of the capacitors we were fitting, it's not as simple as measuring a sample from the rest of the reels to confirm the suitability of the existing stock. Due to the aging effect, and depending on how long the devices have been sitting on the shelf, the measurement might not be valid. I did and experiment on this and my findings confirmed that the capacitance measurements did indeed come back within specification after a half-hour's treatment in an oven. It's also interesting to know that the aging effect starts all over again after it has been reset by an SMT/hand solder process. So, the capacitance value of the component you've fitted to your board will decrease with time. If the component value is at all critical, then the aging effect is extremely significant. I found this via a quick google: http://www.johansondielectrics.com/technical-notes/general/ceramic-capacitor-aging-made-simple.html Brian One interesting (and in my opinion important) thing to mention about the class II ceramic capacitors (i.e. the multi layer ones) is the problem of “aging”. I got caught out by this once, because an ICT system I designed was chucking out a high percentage of product due to some capacitor measurements coming in outside of specification. The capacitors were X7R devices, and removing them from the board and taking measurements confirmed that they were indeed outside of tolerance.
That part of the story worked out fine, but I then decided to investigate the reels of components we have in stock and, to my astonishment, almost every single reel we had (I’m talking thousands of components here) seemed to read out of spec. Curiously, the measurements I made were always *below* the stated tolerance.

My immediate reaction was to complain at the supplier, but a colleague pointed me in the direction of an article about the “Aging” effect on multi-layer ceramic caps. The aging effect, as I’m sure you’re aware, causes the capacitance of the device to decrease with time. This effect can actually be reversed by raising the temperature of the device above a certain threshold (approx 150 deg c I think) and with this in mind it is expected that any SMT or hand soldering process would reset the aging effect and bring the capacitors back within specification. So, whilst we did indeed seem to have a tolerance issue with some of the capacitors we were fitting, it’s not as simple as measuring a sample from the rest of the reels to confirm the suitability of the existing stock. Due to the aging effect, and depending on how long the devices have been sitting on the shelf, the measurement might not be valid.
I did and experiment on this and my findings confirmed that the capacitance measurements did indeed come back within specification after a half-hour’s treatment in an oven.

It’s also interesting to know that the aging effect starts all over again after it has been reset by an SMT/hand solder process. So, the capacitance value of the component you’ve fitted to your board will decrease with time. If the component value is at all critical, then the aging effect is extremely significant.

I found this via a quick google:

http://www.johansondielectrics.com/technical-notes/general/ceramic-capacitor-aging-made-simple.html

Brian

]]> By: admin http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1691 admin Sun, 27 Sep 2009 08:23:41 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1691 Yeah, I don't know what Icon I'd have though? Yeah, I don’t know what Icon I’d have though?

]]> By: Laurent Coustet http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1690 Laurent Coustet Sun, 27 Sep 2009 07:34:38 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1690 'Love the end :-) Thanks for thoses tips :-) ‘Love the end :-)

Thanks for thoses tips :-)

]]> By: Eldon Brown http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/comment-page-1/#comment-1683 Eldon Brown Sun, 27 Sep 2009 01:52:17 +0000 http://www.eevblog.com/2009/09/26/eevblog-33-2of2-capacitor-tutorial-ceramics-and-impedance/#comment-1683 Dave - another good video blog - I always enjoy them! For your web site you should have a "favicon.ico" - that is the little icon that shows up to the left of your URL on a browser - yours is blank at present :-( It is a bit of a Geek-thing, but it is just a little icon file that you put next to your home or index.html page that is read by the browser. Your web master should know what is needed. Eldon Dave – another good video blog – I always enjoy them!

For your web site you should have a “favicon.ico” – that is the little icon that shows up to the left of your URL on a browser – yours is blank at present :-(

It is a bit of a Geek-thing, but it is just a little icon file that you put next to your home or index.html page that is read by the browser. Your web master should know what is needed.

Eldon

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