You know what ? I learn more from you than from my engineering teachers all together .... thank you so much !

Dave, I've been an EE for 28 years, but I'm not ashamed to admit that I learn something from almost every one of your videos. I'm already familiar with most of the material, but you always slip something in that benefits me. I really appreciate what you do. After all these years, I like to think I know everything, but your videos keep me humble. Thanks!

These electronics lectures from Dave are the best part of this channel. Theory and practical experience fused in excellent educational presentations.

smashing video man! As an aerospace guy who's interested in getting more into electronics, these videos are a valuable practical resource I can use to help me understand real designs. I also like how you talk about the basic physics reasons for some circuit designs. My original background is in physics and I appreciate engineers who argue from the physics rather than vague and possibly unreliable rules of thumb. Keep up the fantastic work!

I spent 2 years studying in Polytechnic taking Aerospace Electronics, but you are the only one that taught me more than the book describesd.

Dave; Go get your PhD and teach. We need thousands more like you to make engineering fun for young people.

Again, another great video. I’m a DIY hack and have managed to repair a lot of my own stuff by replacing capacitors. Keurig coffee machine, Kitchenaid refrigerator, Ryobi tool battery charger, Thermador range, and I’m currently repairing an 85 year old Philco tube radio full of bad caps. So yes your comments about longevity are bang on. Trying to imagine how many appliances and electronics have ended up in the dump due to an inexpensive cap failure is like grasping the size of the universe.

Hi Dave, greetings from India. I'm currently in my third year of electronics engineering and I have been an ardent follower of you and your video blog for more than 2 years now. I consider you my electronics GURU [A great teacher] and your clear cut explanation, in depth skill in whatever you do have amazed me to the core. I now aspire to become a person like you. I have a lot to say about you, and your blog. I have got a lot of appreciation and accolades for many of my projects for which i have looked up to your videos for its designing, soldering and many other aspects. You are my electronics GOD. Thanks for putting up all your videos. I wish almighty to shower you and your family with loads of blessings and goodness. Hope you read this. If in case you read this, please try replying.*****

Many thanks Dave, for the practical knowledge that you teach, which can only be imparted by a true electronics professional like yourself!

I love Fundamentals Friday, thanks Dave!

Thankyou Ocker. Im working on a power system, but rechange my ideas as when you near any completion "hindsight" kicks in so I go down that path. Lately the idea of multiple caps came to mind as I want to get good power from fast switching and wasnt sure if big cap would charge up fully fast enough, I understand theres a time restraint but gather its more related to resistance and voltage. You piece is exactly what Ive been looking for - its a real gold mine. This opens my mind to building circuits as Im old school {used to f around with the old Holdens} and hate the "throw away society" when you buy inverters etc... and it goes bumg and you dont know what to do so throw it out and get another - Id rather build my own so they last and anything goes wrong you know what to fix straight away. Long life is what I want as dont want to come to depend on something then have it go bung in the middle of the night. And i didnt know you could get caps on a roll like that. No wonder they can make such wonderful electronics so small and so cheap that do work well. But the crafties dont put ripple protection in them so you keep blowing them. Thanks for your good work.

Your fundamental fridays videos, heck ALL of your videos, should be on a must-watch list for any budding biohacker interested in making their own laboratory hardware. I've learned more from you than most of my intro electronics classes at uni. If I'm ever in Sydney please let me buy you a pint! The least I can do!

I am getting addicted to electronics more and more everyday thanks to your videos ... Thank you sir .. Lot of respect ..

10. Accuracy. You will get a _much_ more accurate (total) capacitance value by using several caps in parallel, since their values follow the Gaussian distribution.

I appreciate the consistent rigor of your real world testing procedures.

This is the kind of practical design stuff they don't teach you in school. Thumbs up for talking about this! This is why new engineers straight from school are often such newbs.

32:24 stephan boltzman constant: "some weird ass funny number you learnt in physics" hahahahaha

Control the question to the easiest possible answer. Way to go there Dave.

Great video. Love learning these practical design concerns like taking temperature dissipation over the greater surface area of multiple caps vs a single larger cap

"Electrolytic Caps 101". Great vid Dave. Chock full of years of practical experience. Suggest making "part 2" next addressing questions raised here in the YT comments and in the forum.

I have been in electronics for 30 years and you taught me a a lot

A great video, Dave. Well explained with diagrams and your usual delivery. That's what makes it so enjoyable! I'll be looking for that video explaining the non-electrolytic caps. Good reason for making #742 after #740. Some great comments on your twitter feed! Keep her lit, mate!

I wondered the same and now know why this occurs Dave! Thanks for yet another great video! Cheers!

thanks mate, your enthusiasm and depth of knoweledge is a pleasure

Great video Dave! A little more about the radiation equation at the end. Specifically, the two temperatures - can and background - are absolute temperatures in K (Kelvin) and not degrees C or F. With a room/background temperature of typically 293K, and the capacitor can higher, the fourth powers of both temperatures are pretty high numbers, and the difference between them exhibits rapid divergence as heat loss through radiation begins to predominate with increasing can temperatures. All good fun stuff.

🎉 absolutely love this practical look at electrolytic capacitors. Learned a lot. Thanks.

good video! The bench demo at the end complements a lot.

I echo all the previous comments excellent video, you present it such a practical and fundamentally useful way........far better than my EE Professor who would write formulas as a stream of consciousness with his right hand across the board as he erased with his left hand. Yep, gave away my age it was a blackboard!

Very nice video, Dave! One thing that was not mentioned (or probably was mentioned but I missed it) was that with more caps you get more self-protection. If one of the caps fails, by having the ESR shooting up, the remaining caps will "protect" it as they will pick up most of the "ESR load". This also will maximize the remaining life (whatever is left) of the faulty capacitor as its "ESR load" will be decreased. (In fact it's more complicated - the concept of "ESR load" is a bit inaccurate) This is in contrast with other situations where a fault in an individual component results in a failure of the whole system. Examples: capacitors or resistors in series. Or a more subtle case is LEDs in parallel, where a LED approaching end-of-life will have a lower breakdown voltage so all current will go through it (mostly) which will accelerate the LED breakdown. Then, then next LED with the lowest voltage takes over, etc.

Another GREAT tutorial video. Very enlightening and informative. Thanks again Dave. Love the demo. A picture is worth 1000 words and gets easily stuck in your head ;)

Nice video. Very practical. I always enjoy the Fundamental Friday videos!

Thanks for these videos. I'm approaching the end of my first year in seriously learning electronics for the purpose of designing and making guitar effects pedals, n similar. Your videos have helped me so so much. You are a great teacher.

Great video series that exhaustively explains a neat selection of problems from a purely practical perspective. Great for honing those basic electronic skills and for refreshing areas you could be taking for granted otherwise.

Brilliant introduction to electronic design. Please make more videos like this.

Hi Dave!!! Always useful, I really love your videos!!! I only want to point out that nearly 13:40 when you explain capacitor dissipation, A1 and A2 are switched in formulas. Apart this, great vlog!!

Dave Gelman...This maybe what you were looking for, if you have not found it yet! "Parallel caps with different capacitance values" Is EEVblog #859...Cheers to anyone searching for it...Bob's your uncle! Enjoy

What is missing is why we use an electrolytic capacitor in parallel with a non-electrolytic (ceramic) one. The video does not focus on the reactance of the buitin self current: electrolytic capacitors have high reactance and this plays an influence on high-frequency peaks of currents (notably those coased by digital gates causing noise currents). The response in fact was only studied at a single frequency forgtetting what happens at noisy high-frequency peaks). That's why we find huge electronic capacitors in parallel with microscopic non-eletrolytic capacitors. The latter will not have enough charge to sustain continuous loads, but will react much better against those noises to absorb them (they will be recharged very fast by the charge of the neighbouring big capacitors. A video could compare the response using a large range of frequencies. Notably by using complex numeric charges like a processor running around 1GHz, and to show the effects of the noise starting signicantly around 3GHz, and how a single ceramic capacitor solves the problem compared to the situation where it is missing and all the stabilisation work is done by the electrolytic capacitor. Start by running your processor at low frequency, then increase it (still in its operational range) and you'll see how the power voltage is being affected by the increasing noise (independantly of the frequency of your power source which is typically 50 or 60Hz. The same is true when instead of a AC-DC power converter source you use batteries : the (electrolytic) batteries react also like capacitors and don't like much the jigh frequency noise: adding a non-electrolytic capacitor in parallel allow them to behave better (and also with less heat dissipated by them, those batteries will also have longer life and will be usable for longer time before being too much discharged.

Wow, I never knew about the heat generated inside a capacitor. That Flir Camera is a wonderful teaching tool.

That was a great video Dave. I first looked at the time and thought to myself "half an hour!, I'll just watch a bit till I'm bored", and before I knew it you were apologising for making a 30 minute vid.

Great video. I wound up using many of these reasons while designing my induction heater. CAP life is difficult to deal with at 75khz and 600amp peak current. Pulsed, 25% duty cycle extends life and reduces heat. Still caught on fire. So I made a modular cap bank that slides in and bolts on. :-P

Thank you... Dave So great class. I wish I had also this kind of class in college.

Please do more fundamental fridays. Best videos thanks! :)

Dave, you are an effing genius! and a fine teacher! Bob's your uncle!

Very interesting. I appreciate the time that went into this. Good engineers always leave a safe margin.

I love how practical this is! I thought there was some deep physics explanation, but nope... It basically comes down to time and money efficiency!!

cheers, EEVblog (Dave), I've never considered the power dissipated in the ESR before, Will be bearing in mind for future applications!

Good video, great topic. Shows many aspects, and the huge discrepantion between the newbees theory in class and the oldguys implementation in industry.

Really good explanation. Thanks a lot, Dave!

Great video m8. Love your edu-videos. Still learning everything I can from you and your people on the forums. I have posted a few times with some strange questions. Overall everyone is really cool. Cheers for educating the world.

Thanks for the sharing and clear explanation. Love it.

Awesome video Dave! I loved your presentation, Spot on!

This video takes me back to my Polytech days. Theory on the whiteboard followed by a practical. Brilliant.

I feel blessed that I found your channel

Great video. I binge watch you on 2X and feel like Neo when I'm done. This video explains why my 1991 Mitsubishi Mirage would eat ECUs (aka brain box for the engine) every three years. After the third one went, I finally opened up the case versus submitting it as a core exchange. I found dielectric had spewed out of a large capacitor. I swapped the capacitor out and got a few more years out of it. In hindsight, I should have rigged up two capacitors in parallel to fix it forever.

Nice instructional videos, Dave

An obscure reason regarding ESR; DC-DC converters have LC filters, typically rather high Q/low ESR as there is a high ripple current. LC filters resonate and you can damp this with an RC snubber in parallel with the capacitor. If you can make something close to this RC snubber out of a single cheap capacitor with about the right ESR rather than expensive low ESR cap and a resistor, that's a win. So you often see a cheap cap in parallel with a low ESR cap in the output of these. You might see this on a second stage filter outside the control loop for example. ESR is my main reason as DC-DC converters / SMPS are my thing. Converters I build have specific requirements for capacitance and ESR for transient response and ripple voltage etc and low voltage, low capacitance caps have much too high an ESR so I might split a cap into 3 to 5 parts for example to meet those specs. I also use expensive solid electrolyte caps from nichicon when I can, but that's impractical in mass produced consumer items.

I appreciate this lesson very much Dave, Thank You!

Thanks, Dave. Good question. Good answers. Didn't mind the time at all.

Very informative and comprehensive!

Thanks, very nice video. Very instructive. (Note: the capacitor surfaces A1 and A2 are swapped 14:17)

Very awesome video! Totally explains it in basic terms. Love your videos!!!

Most informative Dave, thanks. I'll remember this vid next time I'm tempted to just drop a capacitor into a design.

Love to see that dummy load again. excellent video Dave. thanks!!!

Really, really good stuff, thanks Dave.

Hey Dave, that was an excellent explanation, and great demo of what happens, thanks, you're obviously Da Man!!!

Just wanted to thank you good sir. You and some of your peers on KZfaq, has taken electronics out of the realm of black flipping magic and in to the realm of this is easy. By easy i mean most of my components survive an encounter with the on button. You are awesome!

Thanks for your videos! A primmer on surface mount pcb assembly for small to moderate volume would be very helpful

Thank you very much. Very informative session.

Thanks Dave, that video is going to be one of those that will be important to a lot of engineers. Basically timeless. And you skipped #741 as suggested, awww ;) Looking forward to that one now.

I wouldn't ever have thought that the higher voltage caps have a longer lifespan. No way! That's just crazy! There's always another surprise just around the corner!

Yay!!! I love fundamentals friday! Thanks Dave!!!

Another great video! Thanks Dave!

Brilliant. Even I could follow most of that.

This is a really interesting video. I have one quibble, though. For the temperatures and conditions you are talking about, convective heat transfer (either natural or forced convection) will be considerably more significant than radiative heat transfer, so your Stefan-Boltzmann equation is not the one to use. I would use heat dissipation Q=UAΔT, where the overall heat transfer coefficient U depends on the air flow (in the case of natural convection the air flow depends on the temperature difference ΔT).

I love practical production advise like this. People think companies have unlimited resources, and that customers will pay unlimited amounts for devices, but it's just not true. When I worked in automotive, they would have entire programs designs to save literal pennies on fasteners, for example, because they use MILLIONS of a specific fastener. Adds up to real dollars, and whether the vehicle is profitable or not. Same goes with production electronics.

If I had an electronics teacher like you at college, possibly I would have changed to electronic engineering at the time. We had a nasty terrible man... THANKS FOR YOUR WORK!

Good video. I love fundamental fridays!

Great video very educational. Keep up the good work.

Thank you for curing my insomnia. I haven slept this well in ages.

Thanks Dave! Your videos are priceless!

Thanks dave, ive been a repairer for years and never thought about multiple capacitors, i allways assumed it was size restriction only, brain well slapped lol :D Hmm finned heatsinks on can capacitors for longer life...... ditch that heat :)

Great job, making it all so clear. Never knew the simple cap would get so deep. Thanks

That was an excellent demonstration! I also come to discover your FLIP camera is incredibly sensitive. Picking up heat reflected from your hand. I wouldn't have expected that.

Great vid ! opened my eyes to caps big time !!!

Yet again great explanation .Thanks mate.

Hey Dave, nice video, as usual showing real world cases and explaining why they are done! I'm not so sure about the last bit, you only included radiation, but ignored convection which in this case is probably higher than radiation. Thanks for all this videos! JS

Thank you Dave for an amazing video! Can you do some tests if using parallel electrolytics in high-pass circuit does make any difference, or improves linearity?

Fantastic lecture !!!!!!!! Would not wanted to miss it. Would give it 10 Thumbs up if i could. Thank you so much.

Learned a lot about caps, Thanks.

would like to see a video on why back to back electrolytic caps can be used as non polarized.

In my experience electrolytic caps in parallel are most often found in RF Power amplifiers to overcome voltage rating limitations and arc-over issues. They are put in parallel or series-parallel, each with its own bleeder resistor. Commonly with 3K to 5K volts running >100 watts across them.

You're a great teacher dave.

Very interesting video, thank you david.

Thank you so much for this interesting video.

Lots of good items on the "capacitor specs" list, but it's notably missing an important one...working voltage.

Thanks man, that's few good reasons. Sometimes missing on developer this care

Good job on putting the 10 capacitors close together on the breadboard, as on an actual circuit board, they likely would also be crowded close together, and there could be some restrictions upon air flow as well.

Thank you so much for this.

that´s an useful video, good on you dave!

Really like this. I was into electronics before I decided I liked mathematics more and got my first degree in maths. Now that I do mechanical engineering as a profession it's good to get back into electronics as a hobby. I follow this guy with an open Mathcad sheet and have just constructed a sheet that calculates effective capacitance and effective ESR for a multiple capacitor power supply.