I can't even fathom that 10 people bothered to thumbs-down this video. Your videos are prime, sir. This channel is altogether the single most thorough, coherent, and successful delivery of practical, working information, certainly re: electronics, and perhaps everything else on YT.
@@jessihawkins9116what is more concerning is that the TH-cam algorithm will suggest 100 videos of someone building a so called 500W amplifier with a torch, coat hanger, and a random MOSFET... And not this channel.
Great video! Thanks so much for all of the info. I had no idea the marking band on film capacitors indicated the outer foil plate. I was always worried that some film caps were somehow slightly polarized.
Oops, but now folks in the comments are saying manufacturers no longer mark which terminal is the outer foil, but still put the band marking on the cap! I guess it should be tested electrically for really critical applications.
I can't speak to all bu t seems like most professors at Uni. are purely academic and spent little to no time in the field. I believe this guy has spent time in the field as and applications/design engineer.
Fantastic video as usual! There are several Part 2 possibilities if you're so inclined. A deeper dive into the electrical characteristics of capacitors is one. I really appreciate your clear teaching style. What a great service to the community!
Thank you very much for a very informative video. Your explanation is remarkable and with full details. I really watched the whole video without blinking an eye. Your commentary is excellent, very clear voice, very good accent, and very detailed ingredients and comparisons. Thank you so much. it helped me a lot. I liked your video. Sir can you do a vlog with Motor Start and Motor run capacitors? Thanks.
You have to be careful with the "orange drop" caps, and many of the film caps, as the band no longer tells you which is the outside foil. This can be tested by using your scope. Connect the cap and hold the body between your fingers and see how much voltage shows on the scope. Then reverse the leads and test again. It is often the case the band is incorrectly marked. The lowest "noise" pickup will happen when the ground lead of the scope is on the outside foil. This can be important in high gain audio amps. Also Tantalum caps throw in the monkey wrench by marking the Positive lead with a band vs aluminum caps which mark the negative lead with a band.
It's good to see you back posting instructional videos, sir. I am in system engineering/integration and (honestly) am little more than a glorified technician. I find myself in the company of EEs every day and your videos have helped me sound like I know what I'm talking about. =)
First ... I andomly found something form you while searching around for oscilloscope external trigger problem that I had. Then I randomly watched some other video of yours, after that I liked one of your videos, and made me curious "whats this guy actuall posting...." and clicked on channel's name - videos. Ok....now... after seing your list - I subscribed. I will start to watch everything that I like around here, and I want to thank you for your work. Quite amazing.
Nice to see you back making videos Alan. Jim Williams wrote an App Note for LT(#72), which had a subsection on Bypass Caps which is what I would throw into the "must reads" category for anyone doing HF work.
Thanks Alan. With everything I have fixed, I thought I knew just about everything about capacitors. Getting some of the mixed component boxes from Electronic Goldmine has given me a chance to fool around with every type of capacitor you mentioned. Still you found a way (and always find a way) to introduce some new information in these basic component videos. Thanks again!!!
Man your videos never cease to amaze me, on a lot of them I will sit there with my notebook and transcribe your note sheets 👍 the way you break down and organize the data really helps me to onboard some of these concepts. Thank you very much for what you do!
As you may know, the notes sheets for my videos are usually available as a downloadable PDF file. The link can be found at the bottom of the video description on the TH-cam page for each video. For example, the notes from this video are here: www.qsl.net/w2aew/youtube/capacitor_types.pdf
Insane amount of respect for all the effort you’ve put in over the years to educate. My only question is where did you learn all of this stuff? For example this video, is this all industry knowledge? Do you browse academic journals in your spare time? Is it just experience and observation from looking at hundreds of capacitor data sheets? I hope to be one day as knowledgable as you are on anything, thanks again.
Thank you very much, Jesus. Learning all this "stuff" came from a multitude of sources - ranging from years of working alongside some very smart people, reading a lot of good technical articles and books, studying component datasheets, learning from mentors and a ton of trial, error and experience. You know what they say... "Good judgement comes from experience, and experience comes from bad judgement". All part of being in the engineering environment for nearly 40 years...
Big big big thumbs up!!! You've made some excellent videos, but this one is extremely helpful. It's packed with lots of great information. Can't thank you enough.
Another well researched, thoughtful video, full of practical information. Answers a lot of questions I've had when poking around devices I've torn apart and wondered about.
This was excellent. Thanks! I've been searching TH-cam for a good discussion on the types of caps and none that I've seen have covered this in this detail along with use cases.
Hi, I came across your perfectly shot video about capacitors, you talked about the temperature dependence, but it's a pity that you didn't point out the problem with soldering with polystyrene capacitors, it will permanently change its capacity when the terminals overheat during soldering. At present, it is no longer the case that the mark on the capacitor indicates the outer foil and it is necessary to do a hum test with an oscilloscope to identify it. I have met capacitors marked this way many times and often the outer foil was on the opposite side from the brand. Nice day 🙂Tom
Very good video, thanks. I didn't know about about the band on the film caps until now. Always good to learn something new. I would also recommend anyone who hasn't already done so, to have a good look at one of the manufacturers application notes on tantalum capacitors before designing them into your circuit. There's a lot to learn about rated voltages, temperatures, failure rates, etc.
You should merge all the knowledge presented in your videos, mix it with the way you present it and then write a book. This would became the top handbook on electronics and radiotechnics.
This is the sort of information that turns a noob engineer or tech into an advanced one, one of the steps in ultimately earning the title 'senior'. I've been in the business all my life, but I've already watched this twice for small nuggets I've missed.
Alan, another excellent video that I learned much from! Thank you for taking the time to do these videos. Wish they had been around when I was in school!!
Excellent overview of capacitor basics. As Vern noted, the band on many modern film caps no longer accurately represents the outer foil. Paul did a very good video on demonstrating this and how to test them. A recommendation for another cap video is on safety and bypass capacitor applications. When restoring old tube equipment I always install modern X1/Y2 rated caps on the mains input.
One way to tell the difference between Polyester and Poplypropylene film capacitors is that PP in general have much higher Q factor. This requires a proper LCR or capacitance meter, though. Common PE caps have typically a Q value of 100 - 200, whereas PP have >1000 or even >10 000, similar to PS caps and Micas. I noticed that cheap CBB (PP) caps that you can buy nowadays on Amazon, Ebay and from China, have the same Q factor as their similarly looking PE counterparts (Q around 200). I don't really know what's up with that. Maybe stick to known brands, especially for higher frequency stuff where Q matters.
You have answered so many questions I've had about capacitors. Thankyou! Two things I want to mention. My company sent a service memo out stating that they reverse polarized a small rectangular electrolytic cap in production. We had to go into the field and replace them. They would fail after about 5 years. The first one I did I had to remove 32 screws to get to the board!!! I recently bought a very, very expensive ceiling fan with a custom led light. When you turn on the light it hums worse than an amplifier that goes to eleven. I assume this is due to the ceramic caps resonating in the audio range used in the DC to DC converter.
Excellent. I have a box full of salvaged Caps that you have now identified as Mica caps and I can use these for decoupling in my Audio amplifier projects. Many thanks for helping me in identifying them.
Another really great video! I am a scrounger for mica cap wherever I find them since they lately have become so expensive and hard to source. One current source I found at fairly decent price is the SMD ones from Cornell-Dubilier MC Series. Limited stock has been available at RS components. Used many of the 10pF 1000V 1210 ones with very good results.
Another nice (and useful) video Alan. I found it very informative. It seems I am not the only one who has difficulty identifying the dielectric in the plastic film caps.
Thanks, good video, I was confused about the paper caps with the bands when I came across them for the first time when doing a repair on my hp microwave frequency counter (video on my channel) the band threw me a bit!
Love these videos, very well and clear presented. espescially like that you show it with test equipment. many others just talk about theory. well done!
Thanks for another informative and interesting video. Your relaxed style makes for easy listening. I liked your use of a meter probe as an improvised pointer at one point!
Nice tutorial. Those class 2 ceramics are also frequency dependent. Recently fixed an HF BPF where the designer thought they'd save space by using X7R caps in the resonators instead of NP0. They couldn't figure out why it was not working.
So dielectric absorption is the term. I experienced it first hand years ago I just didn't know what to call it. When I used to work on CRT TVs I found that the anode caps regained some high voltage even after discharging them with a high voltage measuring probe (I was able to monitor the slow discharge on the meter). I would equate it to a nasty static shock more surprising than painful. I only had to get bit once when reinstalling an anode lead. I took a wire and installed alligator clips on each end after removing the anode lead I hooked one end onto the CRTs braided ground strap and the other to the anode cap. I only removed this shorting wire right before I was about to reinstall the anode lead. A CRT is essentially a large capacitor there is a conductive surface on the inside of the tube (one plate) the thick glass (the dielectric) and a conductive surface on the outside the gray aqua dag (the second plate). This wire shorts out this capacitor preventing any "surprises" later :-).
So, if I understand this right, the reason you often want a mixture of larger electrolytic caps as well as smaller ceramics, for filtering power supply inputs/outputs, is because the large electrolytics are good at "picking up" the larger ripple voltages, with lots of capacitance to gulp up larger amplitudes, and the small ceramics pick up the smaller-amplitude or higher frequency ripple... And the smaller caps achieve that simply because they're "faster" (smaller ESR)? I think I'm getting it. Maybe!
Yeah, you're getting it. The big bulk caps provide the path for the low frequency currents, and the smaller ceramic (usually) caps take care of the high frequency content. Not so much because of ESR though - it is mainly due to the SRF (self-resonant frequency). See my video on that. The big electrolytic caps have a self resonant frequency well below 1MHz typically, which means that they look inductive above that. The ceramic cap's SRF is much higher, so they still behave as capacitors at high frequency.
Electrolytics: You didn't mention the really wide tolerance of those things, typically -20%/+80%! Also, older US-made parts typically have the positive lead or terminal indicated, asian-made the negative. You also said down to 1uF, but I have salvaged some parts (out of a VCR?) that gave me a bunch of 0.1uF, 0.22uF, 0.33uF, and 0.47uF, all at 50V. I'm not sure why you would want to use an electrolytic in this range of values, though. Tantalum: In a place I was working at some years ago, another tech installed a tantalum cap the wrong way around. The result when he powered it up was rather explosive! Mica: It's apparently the practice of some who work on older (antique?) gear to try and turn one around to be able to see the dots and read off the value. This is a *bad* idea, as you'll then end up with moisture getting into the part and it failing. Also, there are apparently several different coding systems in use, at least 2 or 3, the early Radio Amateur's Handbook showed a couple of them IIRC. Also, there's some parts found in old gear with the brand name "Micamold" showing on the case. These are for the most part NOT mica capacitors, but actually paper! And should all be replaced with newer film caps. One manufacturer of electronic musical synthesizers had an instrument where there were two boards having rows of 22uF/25V tantalum caps and some associated parts. Tied into this was a slidepot that would let you choose the release time of the note(s) you were playing. Unfortunately with the way the whole circuit was configured when you put that slider all the way to one extreme, those caps could end up with 30V across them. I was always rather surprised to find very few failures in those instruments...
I've noticed you've never made a "how to buy a second hand oscilloscope" video, showing what to look for and how to evaluate before buying; I would be very interested in one, both for analog and digital scopes.
I'm a bit late to the video, but... Tantalum capacitors ARE electrolytic capacitors. That's why they are polarized. An electrolytic process maintains the dielectric layer of both the aluminum and tantalum, so you can't reverse the polarity or the dielectric insulation deteriorates and the plates short together. The 2 basic types of electrolytic caps are aluminum and tantalum. 'Non-polarized' electrolytics are simply 2 high voltage aluminum electrolytics (thick dielectric,) that are hooked back to back.
Hi Alan Great coverage on capacitors. One thing on the Polystyrene, and film capacitors on how to find the outside foil end. That Paul Carlson shows how to do in his video on capacitor polarity, using his circuit or using a Oscilloscope with clip leads. The band doesn't always show the outside end of the foil, as Paul shows in his video. I think that you referenced his video once before. Otherwise the video of yours is very informative, thank you very much. I love to watch your videos, they are packed full of information. Later Ray Burke
I just checked my parts box and you are correct Sir, nothing higher than 10nF and was looking for at least 0.1uF for DC offset decoupling of audio. Oh well I will have to scout out some film caps.
with regards to the dielectric soakage discussion, presumably you're in a space with quite a lot of EMF generated by all the equipment and wiring. How do you know that's not just being induced in the wires to create the voltage in the capacitor just through the energy that'll be in the air?
It'd be interesting to see you cover MOVs in this manner. Unless you already have. I only just found the channel lst night and have been binge watching since.
after great introduction to various caps, would you consider to introduce hot to check or measure good,bad or dead caps? there are too much measurement on Electrolytic caps, however rare to detail explain howto check film caps and ceramic caps, thanks
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I can't even fathom that 10 people bothered to thumbs-down this video. Your videos are prime, sir. This channel is altogether the single most thorough, coherent, and successful delivery of practical, working information, certainly re: electronics, and perhaps everything else on YT.
You can't please everyone, apparently.
it’s 11 now. 😏
@@jessihawkins9116what is more concerning is that the TH-cam algorithm will suggest 100 videos of someone building a so called 500W amplifier with a torch, coat hanger, and a random MOSFET... And not this channel.
@@clytle374 I think I’ve seen that video 🤔
@@jessihawkins9116 we've all seen that video, lol
Great video! Thanks so much for all of the info. I had no idea the marking band on film capacitors indicated the outer foil plate. I was always worried that some film caps were somehow slightly polarized.
Oops, but now folks in the comments are saying manufacturers no longer mark which terminal is the outer foil, but still put the band marking on the cap! I guess it should be tested electrically for really critical applications.
Always humbled to hear that I can help teach you something, Ben!
Yeah - Paul at Mr. Carlson's Lab did a good video on that. So much for quality control!
Mr Carlsons Lab has a very good video about this.
Why didn't I get a lecture like this when I was at university? It's just so essential to know all this stuff. Thank you for this.
I can't speak to all bu t seems like most professors at Uni. are purely academic and spent little to no time in the field. I believe this guy has spent time in the field as and applications/design engineer.
I enjoy your videos and I tend to suggest them as reference material for both new and senior EEs that work in my group. Excellent stuff.
Fantastic video as usual! There are several Part 2 possibilities if you're so inclined. A deeper dive into the electrical characteristics of capacitors is one.
I really appreciate your clear teaching style. What a great service to the community!
You did a great job breaking down this subject, especially the difference between different types
Thank you very much for a very informative video. Your explanation is remarkable and with full details. I really watched the whole video without blinking an eye. Your commentary is excellent, very clear voice, very good accent, and very detailed ingredients and comparisons. Thank you so much. it helped me a lot. I liked your video. Sir can you do a vlog with Motor Start and Motor run capacitors? Thanks.
You have to be careful with the "orange drop" caps, and many of the film caps, as the band no longer tells you which is the outside foil. This can be tested by using your scope. Connect the cap and hold the body between your fingers and see how much voltage shows on the scope. Then reverse the leads and test again. It is often the case the band is incorrectly marked. The lowest "noise" pickup will happen when the ground lead of the scope is on the outside foil. This can be important in high gain audio amps. Also Tantalum caps throw in the monkey wrench by marking the Positive lead with a band vs aluminum caps which mark the negative lead with a band.
Yep saw that on Mr. Carlon's Lab
LoL @ your attempt to appear relevant.
You Insecure people are funny... Hahaha
@@jason4547 The irony 🤦♂️
@@billyray1172 Jonny the projection
It's good to see you back posting instructional videos, sir.
I am in system engineering/integration and (honestly) am little more than a glorified technician. I find myself in the company of EEs every day and your videos have helped me sound like I know what I'm talking about. =)
Thank you for producing this comprehensive and well structured overview of capacitors. Wonderful!
Thank you very much, the most up-to-point, informative, fantastic mini-lecture.
Thank you for posting very informative videos such as this. Your knowledge is amazing. Keep up the good work!
First ... I andomly found something form you while searching around for oscilloscope external trigger problem that I had. Then I randomly watched some other video of yours, after that I liked one of your videos, and made me curious "whats this guy actuall posting...." and clicked on channel's name - videos. Ok....now... after seing your list - I subscribed. I will start to watch everything that I like around here, and I want to thank you for your work. Quite amazing.
Nice to see you back. You left out the Flux Capacitor?
I was too afraid of going back in time!
also the required 1.21 gigawatt might have been an obstacle
Nice to see you back making videos Alan. Jim Williams wrote an App Note for LT(#72), which had a subsection on Bypass Caps which is what I would throw into the "must reads" category for anyone doing HF work.
Yes, anything that Jim Williams wrote is in the "must read" category - pure analog genius.
Always great to see w2aew publishing a new video! Thanks for this primer on capacitors, very helpful stuff!
Thanks Alan. With everything I have fixed, I thought I knew just about everything about capacitors. Getting some of the mixed component boxes from Electronic Goldmine has given me a chance to fool around with every type of capacitor you mentioned. Still you found a way (and always find a way) to introduce some new information in these basic component videos. Thanks again!!!
Man your videos never cease to amaze me, on a lot of them I will sit there with my notebook and transcribe your note sheets 👍 the way you break down and organize the data really helps me to onboard some of these concepts. Thank you very much for what you do!
As you may know, the notes sheets for my videos are usually available as a downloadable PDF file. The link can be found at the bottom of the video description on the TH-cam page for each video. For example, the notes from this video are here:
www.qsl.net/w2aew/youtube/capacitor_types.pdf
Looking forward to play with a bunch of Soviet capacitors soon. Thank you for your videos, you are one of my favorite teachers.
Absolutely this is the BEST tutorial on capacitors I have ever seen. Very nice work W2AEW.
Insane amount of respect for all the effort you’ve put in over the years to educate. My only question is where did you learn all of this stuff? For example this video, is this all industry knowledge? Do you browse academic journals in your spare time? Is it just experience and observation from looking at hundreds of capacitor data sheets? I hope to be one day as knowledgable as you are on anything, thanks again.
Thank you very much, Jesus. Learning all this "stuff" came from a multitude of sources - ranging from years of working alongside some very smart people, reading a lot of good technical articles and books, studying component datasheets, learning from mentors and a ton of trial, error and experience. You know what they say... "Good judgement comes from experience, and experience comes from bad judgement". All part of being in the engineering environment for nearly 40 years...
Big big big thumbs up!!! You've made some excellent videos, but this one is extremely helpful. It's packed with lots of great information. Can't thank you enough.
Another well researched, thoughtful video, full of practical information. Answers a lot of questions I've had when poking around devices I've torn apart and wondered about.
This was excellent. Thanks! I've been searching TH-cam for a good discussion on the types of caps and none that I've seen have covered this in this detail along with use cases.
Hi, I came across your perfectly shot video about capacitors, you talked about the temperature dependence, but it's a pity that you didn't point out the problem with soldering with polystyrene capacitors, it will permanently change its capacity when the terminals overheat during soldering. At present, it is no longer the case that the mark on the capacitor indicates the outer foil and it is necessary to do a hum test with an oscilloscope to identify it. I have met capacitors marked this way many times and often the outer foil was on the opposite side from the brand.
Nice day 🙂Tom
Very good video, thanks. I didn't know about about the band on the film caps until now. Always good to learn something new. I would also recommend anyone who hasn't already done so, to have a good look at one of the manufacturers application notes on tantalum capacitors before designing them into your circuit. There's a lot to learn about rated voltages, temperatures, failure rates, etc.
Thank you very much for such a well made presentation. I learn a lot from your videos. All the best, Paul
Thank you a lot. Very detail information, with a good voice. First time i see this channel.
You should merge all the knowledge presented in your videos, mix it with the way you present it and then write a book. This would became the top handbook on electronics and radiotechnics.
Maybe I'll have the time to do this when I retire...
Thanks for the video. As an old/new electronics student, it's nice to see these things explained without too much engineering jargon.
Thank you for removing a lot of the mystery about the different types of capacitors. Excellent presentation.
This is the sort of information that turns a noob engineer or tech into an advanced one, one of the steps in ultimately earning the title 'senior'. I've been in the business all my life, but I've already watched this twice for small nuggets I've missed.
from knowing nothing bout these things few minutes ago i do now. good job explaining. thanx👍
Nicely done, mon ami! Brought back old memories … and created a few new ones!!
Alan, another excellent video that I learned much from! Thank you for taking the time to do these videos. Wish they had been around when I was in school!!
Excellent overview of capacitor basics. As Vern noted, the band on many modern film caps no longer accurately represents the outer foil. Paul did a very good video on demonstrating this and how to test them.
A recommendation for another cap video is on safety and bypass capacitor applications. When restoring old tube equipment I always install modern X1/Y2 rated caps on the mains input.
Yes - Paul did an excellent video on that. Good point about the X and Y rated caps.
One way to tell the difference between Polyester and Poplypropylene film capacitors is that PP in general have much higher Q factor. This requires a proper LCR or capacitance meter, though. Common PE caps have typically a Q value of 100 - 200, whereas PP have >1000 or even >10 000, similar to PS caps and Micas. I noticed that cheap CBB (PP) caps that you can buy nowadays on Amazon, Ebay and from China, have the same Q factor as their similarly looking PE counterparts (Q around 200). I don't really know what's up with that. Maybe stick to known brands, especially for higher frequency stuff where Q matters.
most comprehensive capacitor tutorial i have seen so far, very nice, thank you !!!
Great.....sorely needed Video for beginners.....thumbs up for sure
Awesome video! Geez... You even had a "old buzzard" bread slicer! You didn't miss anything!
You have answered so many questions I've had about capacitors. Thankyou! Two things I want to mention. My company sent a service memo out stating that they reverse polarized a small rectangular electrolytic cap in production. We had to go into the field and replace them. They would fail after about 5 years. The first one I did I had to remove 32 screws to get to the board!!!
I recently bought a very, very expensive ceiling fan with a custom led light. When you turn on the light it hums worse than an amplifier that goes to eleven. I assume this is due to the ceramic caps resonating in the audio range used in the DC to DC converter.
Excellent.
I have a box full of salvaged Caps that you have now identified as Mica caps and I can use these for decoupling in my Audio amplifier projects. Many thanks for helping me in identifying them.
I'd be surprised if the mica caps would be large enough in value to be usable for audio frequencies (unless used in very high impedance circuits).
Perfect summary, excellent by any standard. Thank you for your most valuable time👍.
Very comprehensive - a 'Reference Video' for me!
Another really great video!
I am a scrounger for mica cap wherever I find them since they lately have become so expensive and hard to source. One current source I found at fairly decent price is the SMD ones from Cornell-Dubilier MC Series. Limited stock has been available at RS components. Used many of the 10pF 1000V 1210 ones with very good results.
Excellent overview, best and most complete I've seen.
Bravo, your 2^8 video. Really enjoy your videos and I always learn something.
A comment to upvote the video. Great work, thank you!
Another nice (and useful) video Alan. I found it very informative. It seems I am not the only one who has difficulty identifying the dielectric in the plastic film caps.
Very difficult unless you check out the device manufacturers data sheet.
Very true, Alan.
Thanks, good video, I was confused about the paper caps with the bands when I came across them for the first time when doing a repair on my hp microwave frequency counter (video on my channel) the band threw me a bit!
Love these videos, very well and clear presented. espescially like that you show it with test equipment. many others just talk about theory. well done!
This was a great video! You should do one for inductors too. Thank you
Thanks for another informative and interesting video. Your relaxed style makes for easy listening. I liked your use of a meter probe as an improvised pointer at one point!
Nice tutorial. Those class 2 ceramics are also frequency dependent. Recently fixed an HF BPF where the designer thought they'd save space by using X7R caps in the resonators instead of NP0. They couldn't figure out why it was not working.
Great stuff. Love it. Thanks!
Thank you. Knowledge needs to be shared!
Very good review of capacitor types
Totally informative and useful. Thank you for a well done and explained video on the most popular and visible caps!
Good video Alan, never too old to learn.
This is excellent--the best discussion of capacitor types I've seen. Thanks a lot for doing this.
So dielectric absorption is the term. I experienced it first hand years ago I just didn't know what to call it.
When I used to work on CRT TVs I found that the anode caps regained some high voltage even after discharging them with a high voltage measuring probe (I was able to monitor the slow discharge on the meter). I would equate it to a nasty static shock more surprising than painful.
I only had to get bit once when reinstalling an anode lead. I took a wire and installed alligator clips on each end after removing the anode lead I hooked one end onto the CRTs braided ground strap and the other to the anode cap. I only removed this shorting wire right before I was about to reinstall the anode lead.
A CRT is essentially a large capacitor there is a conductive surface on the inside of the tube (one plate) the thick glass (the dielectric) and a conductive surface on the outside the gray aqua dag (the second plate). This wire shorts out this capacitor preventing any "surprises" later :-).
Yep - I worked in a TV repair shop in the late 70's, early 80's while in high school - learned all about the 2nd anode and the voltage regrowth!
Incredible. I wish you were my EE prof.
So, if I understand this right, the reason you often want a mixture of larger electrolytic caps as well as smaller ceramics, for filtering power supply inputs/outputs, is because the large electrolytics are good at "picking up" the larger ripple voltages, with lots of capacitance to gulp up larger amplitudes, and the small ceramics pick up the smaller-amplitude or higher frequency ripple... And the smaller caps achieve that simply because they're "faster" (smaller ESR)? I think I'm getting it. Maybe!
Yeah, you're getting it. The big bulk caps provide the path for the low frequency currents, and the smaller ceramic (usually) caps take care of the high frequency content. Not so much because of ESR though - it is mainly due to the SRF (self-resonant frequency). See my video on that. The big electrolytic caps have a self resonant frequency well below 1MHz typically, which means that they look inductive above that. The ceramic cap's SRF is much higher, so they still behave as capacitors at high frequency.
Gotcha. Will have to check out that video as well. Cheers!
The smaller capacitors often have a a smaller ESL, not ESR, and this relates to SRF as w2aew mentions.
I'm extremely happy to see that you are getting around better. Ditto all of the other positive comments.
Electrolytics: You didn't mention the really wide tolerance of those things, typically -20%/+80%! Also, older US-made parts typically have the positive lead or terminal indicated, asian-made the negative. You also said down to 1uF, but I have salvaged some parts (out of a VCR?) that gave me a bunch of 0.1uF, 0.22uF, 0.33uF, and 0.47uF, all at 50V. I'm not sure why you would want to use an electrolytic in this range of values, though.
Tantalum: In a place I was working at some years ago, another tech installed a tantalum cap the wrong way around. The result when he powered it up was rather explosive!
Mica: It's apparently the practice of some who work on older (antique?) gear to try and turn one around to be able to see the dots and read off the value. This is a *bad* idea, as you'll then end up with moisture getting into the part and it failing. Also, there are apparently several different coding systems in use, at least 2 or 3, the early Radio Amateur's Handbook showed a couple of them IIRC.
Also, there's some parts found in old gear with the brand name "Micamold" showing on the case. These are for the most part NOT mica capacitors, but actually paper! And should all be replaced with newer film caps.
One manufacturer of electronic musical synthesizers had an instrument where there were two boards having rows of 22uF/25V tantalum caps and some associated parts. Tied into this was a slidepot that would let you choose the release time of the note(s) you were playing. Unfortunately with the way the whole circuit was configured when you put that slider all the way to one extreme, those caps could end up with 30V across them. I was always rather surprised to find very few failures in those instruments...
Great job again; I love re-learning this stuff in a very concise manner! Bravo
thanks, a very comprehensive introduction
Great Video thanks for that
All this time and I didn't know about the banding on the film caps. Thanks
VERY GOOD THANKS .. Didn't know about reverse voltage sensitivity of tantalums !
I've noticed you've never made a "how to buy a second hand oscilloscope" video, showing what to look for and how to evaluate before buying; I would be very interested in one, both for analog and digital scopes.
I'll add that topic to my list.
Thank you ! :)
R
Excellent video, and very informative. Your use of graph paper reminds me of Forrest Mimms' notebooks.
The Mimm's Notebooks were my inspiration to become an engineer in the late 70s, early 80s.
I'm a bit late to the video, but...
Tantalum capacitors ARE electrolytic capacitors. That's why they are polarized. An electrolytic process maintains the dielectric layer of both the aluminum and tantalum, so you can't reverse the polarity or the dielectric insulation deteriorates and the plates short together. The 2 basic types of electrolytic caps are aluminum and tantalum. 'Non-polarized' electrolytics are simply 2 high voltage aluminum electrolytics (thick dielectric,) that are hooked back to back.
Fantastic video I learned a absolute ton about caps!
Awesome videos. Can you make a playlist with the Back to Basic Series?
thank you so much for this video: I took apart an old flat screen tv and wasn't sure how to re-use the capacitors I found on the boards.... :)
Hi Alan Great coverage on capacitors. One thing on the Polystyrene, and film capacitors on how to find the outside foil end. That Paul Carlson shows how to do in his video on capacitor polarity, using his circuit or using a Oscilloscope with clip leads. The band doesn't always show the outside end of the foil, as Paul shows in his video. I think that you referenced his video once before. Otherwise the video of yours is very informative, thank you very much. I love to watch your videos, they are packed full of information. Later Ray Burke
Thanks - yes, Paul's video on the subject of film cap polarity is excellent.
Much appreciated, very helpful. Thankyou.
Thanks Alan, very informative!
I didn't realise how ignorant I was about capacitors. I just want to thank you for passing on your knowledge.
PS. Glad you are feeling better :-)
Still hobbling around with a crutch, but getting more mobile everyday. Thanks.
Amazing video series, I really can't thank you enough. Greetings from Kurdistan my friend
Great video.
I just checked my parts box and you are correct Sir, nothing higher than 10nF and was looking for at least 0.1uF for DC offset decoupling of audio. Oh well I will have to scout out some film caps.
Great material and presentation
Great video thanks
Excellent video, learnt alot! Thanks!
with regards to the dielectric soakage discussion, presumably you're in a space with quite a lot of EMF generated by all the equipment and wiring. How do you know that's not just being induced in the wires to create the voltage in the capacitor just through the energy that'll be in the air?
Another very informative video. One of these years I'll know about .001% of what you do.
such quality informative video... thanks alot sir
Excellent! Good information. Thanks much.
It'd be interesting to see you cover MOVs in this manner. Unless you already have. I only just found the channel lst night and have been binge watching since.
Answered some questions for me. Thanks!
Ive seen polystyrene caps. marked with a band not knowing why - now I do. Thanks.
Great video!
Excellent video thank you.
Really wonderful. Very interesting real life ......
I learn from you .
Thanks
excellent video. thanks for the information.
Excellent videos!
after great introduction to various caps, would you consider to introduce hot to check or measure good,bad or dead caps? there are too much measurement on Electrolytic caps, however rare to detail explain howto check film caps and ceramic caps, thanks
Great video!! How about doing resistor video also. Thanks