Switch mode power supply repair #7: Basics of Pulse Width Modulation (PWM)
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- Опубликовано: 28 авг 2024
- In the seventh video in the Switch Mode Power Supply (SMPS) repair series we introduce the basic concept of power pulsing. Through power pulsing we use a switching element instead of a series resistive element to limit and regulate the average value of the power flowing through the circuit. This is shown through a simple experiment using a push switch and an incandescent lamp.
In contrast to linear power supplies, pulsing supplies are more efficient, since there is no power being dissipated in form of heat on the series resistive element (whether that is a resistor or a transistor).
Next, we introduce some basic concepts related to periodic functions, so that it will be easier to understand the on/off time during a period for PWM.
We look into the period of a function, which is the amount of time it takes to finish a full cycle. The frequency will give us the number of full periods over a given amount of time base.
The frequency expressed in Hz (Hertz) is also discussed, which practically shows us the number of full periods over a second as time base.
These terms are presented using the 50Hz AC line voltage as example, and compared to audio and radio frequency signals.
Since switch mode power supplies operate in a frequency range located at the top of the audible audio frequency range, and at the bottom of the radio frequency range, the periods will be expressed in datasheets either in ms (miliseconds) or us (microseconds).
REPETITION is a very good way of learning/teaching! no one should tell you how to approach the Subject you are doing an excellent Job
Absolutely fantastic Teacher! Back in 1978, we were taught the simple formula that Frequency (F) = 1/t. I have not forgotten this. I am just an amateur that enjoys trying hard to fix broken electronics - whatever they may be. So glad that I stumbled upon your series of Tutorials. Greetings from Australia, and (if you are from Germany - Danke!
Up to now, you're the best teacher I ever encountered. Keep up the goooood work. Thanks a lot.
Please Please finish the smps series! You are the best. Best teacher I ever had.
Thanks for the encouragement! Now my health is a tad better, so I can sit down and make new videos. Btw, I hope that I am not your best teacher, because I consider my videos to have a really bad quality, so if others did even worse than my content, that is...
the SMPS series is very useful for me and you explain very clearly thanks for your effort i love it ;)
This video series is simply awesome, dont stop making them until you covered all and please...please if you can make them more regularly it will be really awesome
Strangly I started to understand when you talked about taxes😁 Masterfully explained video's! Respect!
Yes, money is almost always *that* thing what enhances our imagination. In my view also in high-schools young people should be though more about finances, because it would help them more than high level algebra.
quite informative videos. there can not be a simpler way than this. i have never seen a tutorial like this. please keep it up so that we could get to know and understand the whole concept. we are waiting for ur next video.
What we have, at the end of the day, you're a great teacher Donkey, I can tell you! Thanks!
Thanks Peter, however I still have a lot to learn. When I listen to the videos I was uploading so far, I can barely stand them, they are like a drag. I think that I need to speed up the explanation a bit.
Over 3 years later and this video was just found. Excellent! Thank you! I was shocked to hear you say "sir-kit" :-) "Sir-quit" was ok by me too.
Waiting for the next ones...this is a great series...hope you finish it!
Now I get why it was called a transistor! Excellent video series!
You're very descriptive and give a very good understanding on how this all works. You're helping me learn how these power supplies work and I look forward to more.
Nice explained. Thanks.
Excellent!! You are saying 'circuit' perfectly. I don't know why that bothered me so much, but it made me wince, haha!
I am glad that slowly the videos will come together. Sadly have some issues with my health, so had no time/mood to produce new once. Now I will start and make new videos, and pronounce "circuit" as it should be done, i.e. phonetically. Naah, just joking.
You are a blessing. God bless you for giving help to us.
Many thanks for you positive vibe.
I could definitely use some good blessing, as most of us everyday people.
Wish you all the best as well!
Please upload the next video soon. It is a brilliantly explained video series . Thanks a lot for your dedication
2020 am blessed to watch your videos hope your safe. thank you
Thank man for the comment. Stay safe as well! Keep watching the new videos, if all goes right, I should start uploading again new stuff soon.
Unbelievable, taken me in new directions.... Great series, please keep going, can't wait for 8 and beyond!
Thanks for the positive feedback. Some people do not like it that I try first to explain the basics of how SMPS actually work, otherwise there is no way someone would be able to repair them.
Video 8 is now finally up. It took a while to produce, but hey, I am still around and kicking...
@@DonkeyLearningIT Yes, even to me it seems sometimes bit enlarged. On the otherside i am an absolut beginner and need to be more patient, get learning and finally go to practice exercises to get 'enlighted'. Would be even more fantastic if you could explain all this with practical use of measurement instruments and how to...(i.e. oszilloscopes, freq.counter..). Always a bit worry for cracking them up by wrong steps.
However: Thanks a lot for your good, solid work. All the best for you, Donkey!
@@markusgozzi6738 Thanks for the feedback!
This is the best series about SMPS on youtube, keep on the good work.
Thanks for the feedback. I will try to upload a new video every week, so hopefully there will be the follow-up coming this week.
Thanks to you again after two years , now it 2020 , didn't watch your videos until now ( because of life situation here ) . Keep it up bro
I like the way you explain the electronics topics. Looking forward to your future videos.
Thanks for the comment! I promised to my subscribers that I will upload more frequently, and now I am having a bad cold one after an other. I hope that next week my voice will be at least good enough that one can understand what I am mumbling on top of the slides...
I have been trying to teach myself audio electronics repair for years, I have about a 50/50 success rate with repairs at the component level. I stumbled across your video in the middle of the night, as i was starting to go to sleep, as your video played my mind kept referencing all the times I ve read what you were teaching except now it all started to come together . not realizing I was wide awake I watched every video non stop. I want to say Thank you.I will figure out how to send a gratuity through you tube ...Thanks again.
I appreciate your work put into this series. I subscribed to show you that I'm really looking forward to new videos. Thank you for sharing your knowledge in an area in which there is not a lot of good materials to learn from. Thank you!
Very good video explaining the fundamentals of Pulse Width Modulation.
Finally you're back! The step by step lectures are perfect!
Thanks for watching the vids! Some people want to jump right into repair, but I think that would be the wrong way. There are plenty on "quick & dirty" repair videos out there for people who are impatient. Thus, I will try to make a systematic series of videos instead, where things are covered step-by-step.
Yeah! Exactly! That's what we are talking! If i want "tips" to fix them... i have an "entire" RUclips set of videos... but i'm looking for your step-by-step learning process to be able, "in the end of the day", to understand how they work, and so, perhaps to fix them, too! Your job is "10", how we say over here! Congratulations!
Thanks for this series hope you will be able to complete entire series asap your detailed explanation on all topics are great.
Last year I was a lazy donkey.
This year I will be more productive, and finish the series.
Please make the next video. You are a good teacher.
Thanks for the encouragement people. Have some health issues, but I will be producing new videos soon out of respect, since people keep on subscribing to the channel in spite of me not publishing anything almost 10 months ago by now.
Many thanks, I appreciate that the understanding is important to efficiently diagnosing, and as a bonus provides an insight into electronics which is more practical than theoretical.
Just found your videos and they are awesome and wish you are better in health. Thank you for sharing your knowledge I learn a lot. Thank you again.
Many thanks for the positive comment. Last two weeks I was moving to an other apartment so all my stuff was in storage and had no way to produce a video. However, starting the coming week there should be new videos coming up again. Also wish you all the best, when it comes to health all of us could use some better health and better luck!
@@DonkeyLearningIT that's good to know. I'm new to this still learning, if possible can you make a video ( if have sorry can't find it) on how an op am clearly works and I'm still confuse what an inductor do in a circuit, sorry slow learner here. Thanks again
@@edasplaces6451Regarding the OpAmp, there are several videos out there with hundreds of thousands of views, so I considered that the topic is well covered by people who have larger audiences than my channel. When it comes to the inductor, it will come back as a topic in video number 14 of the SMPS repair series, so do not worry, that will be explained again.
@@DonkeyLearningIT yeah you are right but believe it or not I have try searching someone who explain it like you do and I haven't found one yet, ill keep looking thank you
@@edasplaces6451Well, when I make the videos, I sit down for a couple minutes in order to try to come up with an oversimplified analogy in order to explain things. This might explain why you like the videos. Still, if you check the video on OpAmps from EEVblog, I think it should be still very informative. It has now well over 1Million views, so it has to be good.
Thanks in advance! I shall now enjoy this video! have looked forward for more of your next videos for quite a wile ;)
I just recently stumbeld upon your BGA videos and really appreciated your thoughts and insight. Fantastic videos!
Yeah, most people do not have the patience to sit through those long videos for the BGA repair "guide". However, I wish that someone would have told me those informations before I put more than 1000Euros into an IR reworking station.
Buying a handheld hot air unit is a lot better investment.
Though, now with all those Bitcoin miners out there, the BGA repair might become trendy again.
Hope your health is getting better. Donkey you are the man. Really appreciate the series. :)
This is my continuation of last 6 tutorial 7 th is as usual an excellent presentation.really you are trying your best to explain given subject.thanks for video.
Oh man have I waited.
Thanks so much for continuing this series :D
Thanks for the comment Lord Vader, just do not use the force on me ;)
Joke aside, I will produce more videos this year if my health allows it.
I hope you are OK
At 01:57 Thank You! Thank You! Thank You! for not going over and over things that you have already explained in previous videos :) That way it is not tiresome to go thru your videos, but interesting new content :)
Yeah, I know. Some people like things to be repeated, otherwise they will say in the comment section that video was unclear. Other 50% of people complain, that I should not repeat things. I guess I will have to go with the no-repeat flow, otherwise the videos will be way too long...
@@DonkeyLearningIT - Yes, and by repeating things over of earlier videos will result in each video thereafter getting longer than each previous video :) You have numbered your videos, so it is easy to find the previous videos :)
@@TutterzoidIf each video would be longer than the previous, that would be indeed a problem in the long run. This is why in the newer vids I just mention that if people want to know what is it all about, first they might have to watch the previous video in the series. It is not nice, but it is definitely more practical, especially for those viewers who watch one video after an other.
Many thanks for uploading fantastic series....
Dear Donkey, i like how u say cirquit please do not change. Also love the content cheers
"Sir kit"! Brilliant.
This course is excelent. I'm waiting for the Switch mode power supply repair #8.
pkease continue with this series.compliments of the season
Thanks for the comment. I am ashamed that it took so long to upload a video.
These are good videos i pretty much knew most the important parts and I was looking for a shorter video just to see but here i am
Thanks for going through the video in spite of knowing it already. I hope that it was still informative.
I think these are the best videos ive seen, Thank you very much for all your hard work.
Thanks for the comment. Many people do not realize how much time it takes to produce even these amateur videos, so I cannot imagine what it takes to make good quality tutorials and also make them entertaining and education at the same time.
Yes, please definitely upload more videos this year!
Thank you so much for the videos, you are an amazing teacher.
I first came across switched mode power supply when attempting to fix halogen downlights in our apartment. Expecting to find a simple transformer with diode and capacitor, I found it hard to understand the strange circuit. There was scant information online, until I saw this series. Your lessons have been most beneficial. I now have several failed units that I would really like to fix. Looking forward to the next lesson.
You are really a v.good teacher
very nice video can,t wait for the next video.please upload the next part
as soon as possible.
Thanks
Best tutorial ever in electronics
Please add more videos in this series
I am waiting. For next lecture Tks for all the previous lectures
Thank you, very good explanation.
I really like and understood the way you explained.
Thanks for the comment. There are more videos in the series, so if you got the time, go through them.
Also, in the next year I will upload more content.
I really like your videos. You have done an outstanding effort. Please make rhe next part if circumstances permit you. Thanks.
thanks soo much for sharing your knowledge .looking forward for the next video ..
Thanks for watching and commenting. I am now already working on the 8-th video. I intend to upload about 4 videos per month, so it should go faster.
nice explanation, waiting for next lecture.
I started working on it. No promises from my side when it will be up, but hopefully it will take less than 5 months.
You ar the best teacher ever ... keepit like this
Fantastic series, can’t wait for the next part 👍
Hopefully this time one will not have to wait 5 month for the next video ;)
To my surprise, the number of views and subscribers/comments was growing in spite of not publishing new videos, so I said to myself that I cannot just disrespect people and not do my part of the deal...
There is no deal here, but you are an exceptional organized person, with fantastic teaching skills. I'm an electrical engineer myself, watching your videos for the pleasure of finding out how clear and simple looks your explanations for everybody, not necessary a specialist. I think it is an art to know how to select as few basics as necessary and slowly blend them in, towards the goal of completely understanding functionality of switch power source, no matter how dummy one might be. Congrats. If you could continue this series to the end, it would be a great service for a lot of people.
Thanks for the positive comment, really appreciate it. The idea of the series is *exactly* to explain these things to people who either did not have the time or the money to go and attend an engineering school. I honestly think that the current education system is broken. My small channel will not change that, but at least I might be able to help out a couple people.
it has been three months now since your reply !! :) anyway I will keep waiting ..
@@DonkeyLearningIT
iam glad that i watched your videos.
they are full of knowledge
cant wait for more vids on power supply switch mode or tv repairing in general.
continue your good work.you are really helping many of us
nice teaching i can understand everything thanks.
Superb teacher!!!
Hey, nice video thank you very much. Waiting for the next.
I would love to see the next episode. Please resume the serie. Thank you....
Ok ready for #8 please. Great work.
What a pleasant voice. Yes you are pronouncing "Circuit" better, but I liked the way you did pronounce it - lol. A lot, lot of detail dude. We still haven't gotten to the repairs yet, but it is important to understand the theory for the youngsters.
Thanks man... upload next series ASAP!!!
I need to finish those videos first. My video creation toolchain is very inefficient, so it takes me hours to produce a half-decent 20 minute video. I hope that this will improve when I publish vids more often.
Finally...part 7 arrived.
Yeah, I was having issues with my health (I hate winter...) and being busy with my job as usual. Still, in the future I should take this channel seriously.
If I would have put in a bit more effort, there would be a lot more contents uploaded.
Take your time. But please complete this series. This is the best series on SMPS on youtube.
Thanks soo much for sharing your knowledge .Waiting eagerly for the next video ...
Thanks for watching the video. I hoped I will soon upload new vids, but about three weeks ago I got a bad cold, and since I am just useless. Still coughing, and taking darn antibiotics...
Sorry to hear you catched a cold and i hope you get well soon.
Great explaination. ..waiting for part 8.
good going sir ...please continue your vdo series
your are just great ... waiting for 8 part
Thank you very much sir, I'm wait for next tutorial video
Great stuff'! Thank you!
nooooo, I loved the way you pronounce circuit
u are so great sir.thanks for sharing.keep it up.
The contents could be better (especially the audio is clicking because of the cheap microphone I am using) but hopefully it is still good enough.
Best ever ! Take some Dropi for winter.
Sadly too late for that )
Excellent!
Danke Danke Danke. Enfach toll !
Sehr gerne!
Another Excellent job !!
Thanks for sharing your knowledge, and thanks for getting back again
Thanks for watching!
It took almost five months for publishing an other video, and that *is a shame* on me. In this year I will publish stuff more often, since people are actually watching the videos, which surprises me.
It's because you are explaining it correctly and you are into the stuff, which makes it interesting.
Keep it up, you are doing it great :)
where to donate ? I mean it , man you are awesome !!!
Thanks for expressing your willingness of supporting the content financially. I really appreciate it! Never wanted to make money from the content, but so many people have asked me about this, that most likely next week I will put up a PayPal button for people who got money to spare. With a bit of money invested I could buy better equipment for the channel, or even teardown/repair items. For example, the camera I am using is an 8 year old Canon.
love the videos...ty for the attention to detail!
Ahhhh.. Been waiting for part 8 everyday is waiting......
Lol.Right my cormade?!...9 months neow.... I hope when he releases more it's just all the rest of the series at once so I can binge hardcore lol.
@@user-be4yc2vr5c yeah
I am not running good with my health, this is why I have not uploaded new videos.
I have actually recorded a new one couple months ago, but it just sounded awful, even I could not listen to it. However, I will continue the series, since people keep encouraging me in spite of the bad quality videos I uploaded so far to produce more.
Sorry to hear that sir, i pray for your fast recovery. God speed
Way to rough on yourself comrade, check my other comment if you're truly that self conscious about it. Your videos are also some of the best on all the internet to, but nice modesty. @@DonkeyLearningIT
I was just wondering about you the other day. Wondering if you had given up on this, a danger I had mentioned to you. Thanks for continuing. Waiting to hear about Shottkey diodes and MOSFETS. Probably next year 😉
I do not give up easily. Got the patience of a donkey ;) That is why I got that as my username. Though, the pace got really-really slow, so now I need to shift gear and pick it up. As for Shottkeys and MOSFETs, we might do it this year if all goes "horribly right". Just joking, it should not take that long.
Whatever you do it is appreciated. Don't knock yourself out.
Great tnx, waiting for the next
waiting for next one
Trust me, I am also waiting a while ago for getting a bit better in health.
If all goes right, this weekend I will upload a new video in the series.
Good explanation
Thanks for the comment. Keep on hustlin ;)
where is the 8th ? you are very good at explaining and teaching, without to mention your great spoken english. let me know, please, when you will launch the 8th video. i'm looking forward to it.
good work
hey Sir, been some time since you make more excellent teaching video. Praying you are ok and will return to us soon.
God bless
Same gettin' worries about him. lol.
Sadly I am not doing very good in the health department, this why I have no new videos made.
However, I will take time and upload new videos soon.
@@DonkeyLearningIT good to here you are o.k.take yuut yes you have a fan club. Cheers
I meant ,take it easy.
Expecting the 8th chapter.
Who ever told you to change the way you pronounce that term ("Cir-Quit") needs to just go away. We appreciate the authenticity and uniqueness of your tutorial and way of teaching. And that includes the way you pronounce the terms.
I think you missed to post 8th video of series switch mode power supply repair basics, so i kindly requested you to plz post it quickly, i really liked your previous videos of this series
Thanks
makes no difference to the point of the lesson but there are 365 days in a year. Great videos you have presented on power supply theory.
Haha I was scanning the comments to see how many viewers mentioned it. No wonder the years seem to go faster 😅
absolutely great stuff
THQ,TKQ thank. You. Love it.
More or less 50 weeks a year
Well it's always more and also what 355 days if you are going to cut off 10 days why not 15 and make it 350 or just 300
You are being hard there, why not taking 10 days for holidays ? does not trouble me.
Great video !!
Thanks for watching. Btw, if you have the time, go through the whole series.
When you will make video on power factor correction (PFC) .
I have already watched most of video .
I love the video but I simply cannot understand how a transistor can act as a resistor, especially since the resistance between the collector and emitter is very small whenever the transistor is on. Can you please explain this, Thank you.
Explicit.. Excellent.👊
Thanks for watching. I try to share my little knowledge I got
Woohoo your back!!!!!!!!!
I am saying the same like Bender on the first episode of the last season of Futurama: Yeah, we are back!
Good one. i have viewed all the 7 videos, but where is the continuation?
Many thanks.. so when is the part 8?... cant wait...