I am always impressed by your ability to draft up a circuit, in realtime, with annotations, explanatory notes, colour keyed current flows, and graphs. All while running a narrative. Your brain works in ways mine doesn't, and we all benefit from your desire to teach. Thank you!
@@LearnElectronicsRepair Good explanation but would it be important to have two capacitors rather than one, and also is it really important to change the squar wave for a sinewave? Because the circuit get bigger and bigger and the purpose of it seems strange as the square wave can just as do the job???
@@DailymailnewzWell yes, it's important to have two capacitors. If you had only one capacitor, you would have no Junction between the two capacitors; and it's important to have the LLC circuit for more efficiency.
the best explanation in my 20 year line, even if 1 capacitor is bad the smps won't work, have 3 cooler master smps 2 with active pfc, trying to repair since ages, no 5Vvsb present in all.
You have missed your calling, you should have been an instructor. You are to clever to be playing around with flea market old stuff. Your knowledge is immense and you put it over well.
In schools and universities, you have to follow study plans, deal with students who don't even want to be there. On RUclips, it's different. You were probably looking for a video on the topic of power supplies and you have an interest, and that's why you learn. And don't get me wrong, I also believe that the video's author has an incredible teaching ability.
Fan fook in fantastic! That was brilliant - I was losing it a bit up until the bell analogy came in - the summary brought it all into perspective. Lots learned - thanks very much - 40yrs guessing made easier watching this 👍
Your explanations are gold. The fact that you explain what happens to the wave while it passes through the components and why the components are where they are, makes all the difference. Cheers.
Since discovering your videos I can't seem to watch any other electronics repair guys, they bore me. I'm still learning and you're making it enjoyable.
Thanks for another great vid. I'm an electrician with limited electronics knowledge (I dabble at fixing gear for myself, friends + family, mostly because I love fixing instead of replacing). I already knew a lot of what you explained but I still learned a lot. Every day's a school day. p.s. Parents: go easy on kids who take their toys apart - they may be studying electronics early but you don't realise it. :)
Loved the bell . Always thought about the resonance but genius to think of the pendulum as a square wave . No matter how quickly or slowly you hit the bell with the pendulum, the bell still rings at its resonant frequency . Genius .
The LLC circuit explanation is great. I'd often wondered about that, as it seemed logical that sending an analogue device like a transformer a square wave would not be doing the system much good from a noise perspective. The bell analogy will stick in the head nicely, thanks!
Thank you for explaining this along with the LLC part of it. I never quite understood the way it worked, but the way you explained it nicely. It smooths the sharp edges of the square wave.
I really enjoyed watching this video. So much so I'll be watching it again and maybe a third time. Your analogy with the bell was a good one. Brilliantly done. 😁😁
That makes sense to me now why the transistors went short on the other video when one of the filter caps was open circuit. Thank you for these videos it really does help me understand.
As always, a video full of well dispensed knowledge. Side note : not all LLC circuits are resonant. They do transform square waves into sinusoidal waves but it is not what it is called resonance. In a LLC circuit and basically all RLC circuits, resonance occurs at a certain frequency. The phenomenon is a noticeable voltage therefore current increase in the circuit due to combined characteristics of all components. Often, accidental resonance means destruction of the circuit. The same phenomenon applies to physical oscillators. That's how wind or troops walking at pace can destroy bridges.
Thanks so much Richard. You pretty much answered any questions I had. I have a few on the bench currently, an ATX psu from a customer computer that came in. swapped for a good one now I'll look at this one. I've got a bazillion of them here to play with.
I learned a lot! I always thought transistors were low voltage devices. I can see now that I could fry my oscilloscope if I were to randomly probe transistors inside one of these supplies!
Be careful connecting your oscilloscope to the collector or drain of a FET switching transistor. I have done it but don't recommend it. Best to use a high voltage probe to prevent damage to your scope.
Addicted to your videos now, so glad I found this channel, I have learnt so much and find your description of circuits very clear and easy to understand. Thank you sir
Brilliant job , one of your best yet. Thanks. So , if you did change the value of BOTH of the large caps to a lower capacitor value (not voltage rating) it would still work but at a lower max output .
I am fixing an old Iwatsu scope's power supply and it has dual diodes for 12V, -12V and 5V rails and the anodes are actually connected together. And a single 4ns rectifier diode for the 54 volt rail. Not sure if it was done for added current handling, but the specs for rectifier diodes were hard to meet with newer components when I looked for replacements. The 54volt rail consumes the least current so they used an ultrafast 1 amp diode for it, but other rails are higher current. I ended up replacing the 1 amp diode that had burned with a 4 amp rated diode that had a matching forward voltage/current curve all the way to 1 amps. And I only found one that had matching speed, capacitance and forward voltage when I looked up from Mouser :)
Thank you for commenting and attaching this video, it's a new to me, but I've watched it. I mean the video :D cause I didn't have LIKE on it till now. But, I will use it for my apprentices and technicians as it's a GREAT resource for them to learn. Like a all in one :).
Quite a good presentation. Liked the bell analogy. I'm honing my understanding of the functions of and the relationships between these components and the resulting outcome. With your help. I really appreciate it. Would it be I were just approaching career age level of life, but that is not the case. Strangely, I never feel like an 'old dog'. Never have felt fully 'grown up'. I suppose my inate sense of curiosity multiplied by a strong desire to understand things, (and then put that to use)divided by my age , in years√ has helped to learn new tricks, everyday, which we all know, an old dog cannot. There may be an algebraic formula in the preceding lines, and it may need to be revised, and I would absolutely and happily accept any input from you all out there in comment land. 👍
a good video. Most of the power supplies I have worked on with 2 smoothing caps have either been as you describe here or they are 110 240 switchable or even autosensing using a thyristor between midpoint and bridge for 110 240 selection, of course, most modern PSU's have PFC so no need for the selection.
I was waiting for him explain the clever way of allowing a 120/240 voltage selector for free in the design as well. like this i.stack.imgur.com/1jiaD.png
You really do make a great teacher! Some of the others just run through everything g way to fast at least for me. Not enough time to think about what they are saying, but you are great!!! Thank you! I said this before but you should build a single to 3 phase converter. I think it would get a lot of views
im sorry, in respect to your knowlage of electronics love your work (1) {12:45}' neutral is zero ' my understanding any A.C. current is ( positive is above zero & negitive is below) though we do see it in a way it apears to flip over, (2) i had this problem myself with R.F. high frequency a.c. ...ground, neutral, earth, ..and i will say thank you for sharing you knowlage with us cheers
Thank you again! I kind of got it, well I thought I got it, until it hit me... Why take an AC signal and convert it into DC, just to turn it back into AC? Seems like a waste of energy and components. Silly question? I'm really trying to understand this, and your help is invaluable.
Not a silly question actually. So the mains is AC but a high voltage. We need a low voltage DC. Yeah you are correct in wondering about this, because in many cases the power supply has active PFC, which basically does the conversion 240C AC --> 380-400V DC --> low voltage AC --> low voltage DC. I'll think about how best to explain this but the answer is most probably it is the most efficient way to do it.
@@LearnElectronicsRepair I think the easiest way is to say that for higher power applications it's much more efficient, much smaller and much less expensive than a linear transformer PSU at 50/60Hz - DC is required so it can be 'chopped up' into a much higher frequency AC which can work with relatively tiny transformers, the main downside being noise. Probably not the best explanation but it's what's in my head :)
@@LearnElectronicsRepair But I'm referring to the pulsed DC on the high voltage side, at timestamp 28:00. So, with the answer from @budgiefish, it means that the sole purpose is to speed up the frequency?
Yeah, we can have a look at that. One of the PSU I rejected when making this video (as over complicating things) has the 240V/120V selector and it simply shorts two points on the PCB when set to 120V
For 120V, the center of the 2 caps is tied to the AC neutral. The diode bridge charges one cap on the positive half cycle, the other on the negative half cycle. It's basically two half-wave rectifiers, AKA a voltage doubler, to get 320V DC from 120V AC.
Why rectify the AC, only to convert to +/- square wave to put through a transformer? Why not stick the AC straight into the transformer to derive the lower voltage rails, then rectify only on the secondary sides? Especially if sine waves are more efficient at driving transformers than square waves? Just discovered your channel -- you're the first person I've seen explain ATX power supply topologies in this much detail. Thank you!
@fixfaxerify Intentional. In this circuit the transistors are almost always BJT. In fact I've never seen ATX use mosfet here, though the 5V STB supply is usually mosfet driven
I am always impressed by your ability to draft up a circuit, in realtime, with annotations, explanatory notes, colour keyed current flows, and graphs. All while running a narrative. Your brain works in ways mine doesn't, and we all benefit from your desire to teach. Thank you!
Thank You 😊
I mentioned your post to my wife and she want's to point out that in her opinion I'm (like all men apparently ) hopeless at multitasking 😂😂😂
@@LearnElectronicsRepair and thats why your wife loves you sir!
@@LearnElectronicsRepair Good explanation but would it be important to have two capacitors rather than one, and also is it really important to change the squar wave for a sinewave? Because the circuit get bigger and bigger and the purpose of it seems strange as the square wave can just as do the job???
@@DailymailnewzWell yes, it's important to have two capacitors. If you had only one capacitor, you would have no Junction between the two capacitors; and it's important to have the LLC circuit for more efficiency.
I didn’t realize the video was 42 minutes long until it was over. Well done.
I'm just 7 minutes into the video and this is the most I have learned about power supplies.
agree
the best explanation in my 20 year line, even if 1 capacitor is bad the smps won't work, have 3 cooler master smps 2 with active pfc, trying to repair since ages, no 5Vvsb present in all.
This was an excellent presentation on how this type of PSU operates, the bell analogy for resonance is the best I've seen.
the effort put here is so impressive.
Universities must include this to better their lecture
You have missed your calling, you should have been an instructor. You are to clever to be playing around with flea market old stuff. Your knowledge is immense and you put it over well.
In schools and universities, you have to follow study plans, deal with students who don't even want to be there. On RUclips, it's different. You were probably looking for a video on the topic of power supplies and you have an interest, and that's why you learn. And don't get me wrong, I also believe that the video's author has an incredible teaching ability.
The thoroughness and pace is very appreciated.
Fan fook in fantastic! That was brilliant - I was losing it a bit up until the bell analogy came in - the summary brought it all into perspective. Lots learned - thanks very much - 40yrs guessing made easier watching this 👍
Very informative, feel like i am back in school, new suber after watching this. Ty for your effort and time.
I have learnt more in 45mins with you than any other presenter
Your explanations are gold. The fact that you explain what happens to the wave while it passes through the components and why the components are where they are, makes all the difference. Cheers.
Since discovering your videos I can't seem to watch any other electronics repair guys, they bore me. I'm still learning and you're making it enjoyable.
Dear. Rich, bell analogy to explain LLC topology is simply...fantastic! Never thought that way...regards from Italy.
Saluti 🙂
practically explained perfectly ... the bell was the obsolute example for a resonator 😊😊👍👍👌👌
Thanks for another great vid. I'm an electrician with limited electronics knowledge (I dabble at fixing gear for myself, friends + family, mostly because I love fixing instead of replacing). I already knew a lot of what you explained but I still learned a lot. Every day's a school day. p.s. Parents: go easy on kids who take their toys apart - they may be studying electronics early but you don't realise it. :)
You are the best teacher I never had.
I learned more about circuits and electronics in 42min. than 4 years in the University.
Thanks! Another brilliantly explained subject.
Loved the bell . Always thought about the resonance but genius to think of the pendulum as a square wave . No matter how quickly or slowly you hit the bell with the pendulum, the bell still rings at its resonant frequency . Genius .
@Dave T , Yeah exactly that! The pendulum/hammer/clanger injects🙂 energy into the system but the resonance does the work
Of several youtube videos on this subject, your video was by far the best explanation. Thank you!
gave you a thumbs up especially for the bell analogy
This is the best power supply explanation on AT I have seen ! Thank you very much. Raj (India)
Very good Richard. Many thanks.
Very helpful to my understanding of PSU. The fact you add a sketch to explain things is great.
Nice job. Thanks for the description, very visual, loved the bell analogy, I will use that.
The LLC circuit explanation is great. I'd often wondered about that, as it seemed logical that sending an analogue device like a transformer a square wave would not be doing the system much good from a noise perspective. The bell analogy will stick in the head nicely, thanks!
Very well explained, in fact, clear as a bell.
Yeah I never saw a quality bell that was glass.
Thank you. I thought the bell was the best part 🙂
Thank you for explaining this along with the LLC part of it. I never quite understood the way it worked, but the way you explained it nicely. It smooths the sharp edges of the square wave.
I really enjoyed watching this video. So much so I'll be watching it again and maybe a third time. Your analogy with the bell was a good one. Brilliantly done. 😁😁
Cheers Edwin, I was really chuffed with the bell when I thought of it
Really enjoyed this explanation mate.
Thanks for taking the time to put such effort into this video.
That makes sense to me now why the transistors went short on the other video when one of the filter caps was open circuit. Thank you for these videos it really does help me understand.
As always, a video full of well dispensed knowledge.
Side note : not all LLC circuits are resonant. They do transform square waves into sinusoidal waves but it is not what it is called resonance.
In a LLC circuit and basically all RLC circuits, resonance occurs at a certain frequency. The phenomenon is a noticeable voltage therefore current increase in the circuit due to combined characteristics of all components.
Often, accidental resonance means destruction of the circuit.
The same phenomenon applies to physical oscillators. That's how wind or troops walking at pace can destroy bridges.
Great video! I had some prior understanding how ATX power supplies work but this video explained some details I wasn't previously aware of.
That was great, thanks for not getting bogged down in the resonant imaginary components!
Thanks so much Richard. You pretty much answered any questions I had. I have a few on the bench currently, an ATX psu from a customer computer that came in. swapped for a good one now I'll look at this one. I've got a bazillion of them here to play with.
Excellent video ... worth watching several times to internalize. Thx!
I learned so much from this video, I feel like I owe you money now 😂. Thank you so much for this. You have a new subscriber.
The world's best teacher thanks sir
Thank you for making the operation of that circuit easy for me to understand,. I really enjoyed yout explanation.
I appreciate the clear explanations, as well as saving power supplies from the e-waste bin.
Great explanation Richard. Love the Bell idea, it makes sense. Many thanks
Brilliant! Devastatingly useful! Thank you! Liked and Subscribed.
A good simple explanation, of a complicated circuit. Thank you.
GOLD. The bell made it much easier to understand it.
Very well explained as always. Thanks Richard
this video tied up so much about what I learned from you in past videos - thx!
Brilliant Explanation! I don't recall a great explanation in my electronic classed where theory meets reality. I really enjoy your videos. Keep em on.
I learned a lot! I always thought transistors were low voltage devices. I can see now that I could fry my oscilloscope if I were to randomly probe transistors inside one of these supplies!
Be careful connecting your oscilloscope to the collector or drain of a FET switching transistor. I have done it but don't recommend it. Best to use a high voltage probe to prevent damage to your scope.
A video that could be helpful:
ruclips.net/video/xaELqAo4kkQ/видео.html
Much obliged for your amazing work in educating us!!!
Addicted to your videos now, so glad I found this channel, I have learnt so much and find your description of circuits very clear and easy to understand. Thank you sir
Great explanation I was wondering why there's two caps instead of the usual 400V caps, now it makes sense. Thank you
Brilliant! Many, many thanks! I have to say, all of your tutorials are simply amazing. I have learnt so much. Thank-you again!
Fascinating - great design and explanation.
thanks for your teaching you do a great service for the people who like the electronics. long live with the god's blessings....
ding dong.............. ive never heard it put like that before. it really makes the point. thank you richard
Thank you, thank you, thank you! I learned a lot of very helpful information and now understand this stuff better!
Thanks for the recap on Bridge rectifiers, hadn't seen that since 1st or 2nd year Electrical engineering degree.
Excellent explanation of LLC resonator circuit for higher efficiency. Thank you very much.
Brilliant job , one of your best yet. Thanks.
So , if you did change the value of BOTH of the large caps to a lower capacitor value (not voltage rating) it would still work but at a lower max output .
Explained very well. Thank you.
Brilliant work. Really clear. Thank you!
I am fixing an old Iwatsu scope's power supply and it has dual diodes for 12V, -12V and 5V rails and the anodes are actually connected together. And a single 4ns rectifier diode for the 54 volt rail. Not sure if it was done for added current handling, but the specs for rectifier diodes were hard to meet with newer components when I looked for replacements. The 54volt rail consumes the least current so they used an ultrafast 1 amp diode for it, but other rails are higher current.
I ended up replacing the 1 amp diode that had burned with a 4 amp rated diode that had a matching forward voltage/current curve all the way to 1 amps. And I only found one that had matching speed, capacitance and forward voltage when I looked up from Mouser :)
Thank you for this very detailed and easy to understand video. And yes, i did like the bell analogy! :)
Thank you for commenting and attaching this video, it's a new to me, but I've watched it. I mean the video :D cause I didn't have LIKE on it till now. But, I will use it for my apprentices and technicians as it's a GREAT resource for them to learn. Like a all in one :).
Thanks for the very educational video. LLC is a new thing (at least it is to my old brain when thinking about SMPS LOL).
Quite a good presentation. Liked the bell analogy.
I'm honing my understanding of the functions of and the relationships between these components and the resulting outcome. With your help. I really appreciate it.
Would it be I were just approaching career age level of life, but that is not the case. Strangely, I never feel like an 'old dog'. Never have felt fully 'grown up'. I suppose my inate sense of curiosity multiplied by a strong desire to understand things, (and then put that to use)divided by my age , in years√ has helped to learn new tricks, everyday, which we all know, an old dog cannot.
There may be an algebraic formula in the preceding lines, and it may need to be revised, and I would absolutely and happily accept any input from you all out there in comment land. 👍
Great video, very well explained.
a good video. Most of the power supplies I have worked on with 2 smoothing caps have either been as you describe here or they are 110 240 switchable or even autosensing using a thyristor between midpoint and bridge for 110 240 selection, of course, most modern PSU's have PFC so no need for the selection.
I was waiting for him explain the clever way of allowing a 120/240 voltage selector for free in the design as well. like this i.stack.imgur.com/1jiaD.png
Great Stuff ! Thank you, Richard.
You really do make a great teacher! Some of the others just run through everything g way to fast at least for me. Not enough time to think about what they are saying, but you are great!!! Thank you! I said this before but you should build a single to 3 phase converter. I think it would get a lot of views
Love this video Richard! Thank you!
Great explanation I loved it '👍
im sorry, in respect to your knowlage of electronics love your work (1) {12:45}' neutral is zero ' my understanding any A.C. current is ( positive is above zero & negitive is below) though we do see it in a way it apears to flip over, (2) i had this problem myself with R.F. high frequency a.c. ...ground, neutral, earth, ..and i will say thank you for sharing you knowlage with us cheers
Great explanation, always enjoy your videos...
Good explanation, thank you.👌🍒
Great explanation ! 🥂
Brilliant, very well explained 👍
Thank you again!
I kind of got it, well I thought I got it, until it hit me... Why take an AC signal and convert it into DC, just to turn it back into AC? Seems like a waste of energy and components. Silly question? I'm really trying to understand this, and your help is invaluable.
Not a silly question actually. So the mains is AC but a high voltage. We need a low voltage DC. Yeah you are correct in wondering about this, because in many cases the power supply has active PFC, which basically does the conversion 240C AC --> 380-400V DC --> low voltage AC --> low voltage DC. I'll think about how best to explain this but the answer is most probably it is the most efficient way to do it.
@@LearnElectronicsRepair I think the easiest way is to say that for higher power applications it's much more efficient, much smaller and much less expensive than a linear transformer PSU at 50/60Hz - DC is required so it can be 'chopped up' into a much higher frequency AC which can work with relatively tiny transformers, the main downside being noise. Probably not the best explanation but it's what's in my head :)
@@LearnElectronicsRepair But I'm referring to the pulsed DC on the high voltage side, at timestamp 28:00. So, with the answer from @budgiefish, it means that the sole purpose is to speed up the frequency?
really enjoyed the video
and learnt something new
what an awesome explanation :)
Great analogy! Love the video
the video was very informative , thanks
Yes i did learn, apreciate it.
Very nicely explained !!!
Thanks!!!
How do you get the power for switching controller before it sets up the main transformer?
Great video. Thanks
Very interesting watched pretty much the whole thing, wish there was more on what's driving the two power transistor bases though .
Thankyou. Awesome tutorial
Love the bell anology.
Amazing ability to tech complex ATX PSU. Pls make some latest ATX PSU anatomy.
Go Ahead.
Good work!
You are a legend. Thank you.
On older supplies they have a 110/240v selector, somehow the selector changes the capacitor config to a voltage doubler
Yeah, we can have a look at that. One of the PSU I rejected when making this video (as over complicating things) has the 240V/120V selector and it simply shorts two points on the PCB when set to 120V
For 120V, the center of the 2 caps is tied to the AC neutral. The diode bridge charges one cap on the positive half cycle, the other on the negative half cycle. It's basically two half-wave rectifiers, AKA a voltage doubler, to get 320V DC from 120V AC.
Why rectify the AC, only to convert to +/- square wave to put through a transformer? Why not stick the AC straight into the transformer to derive the lower voltage rails, then rectify only on the secondary sides? Especially if sine waves are more efficient at driving transformers than square waves? Just discovered your channel -- you're the first person I've seen explain ATX power supply topologies in this much detail. Thank you!
Thanks for this explanation. You drew the transistors as BJTs was that intentional or a mistake?
@fixfaxerify Intentional. In this circuit the transistors are almost always BJT. In fact I've never seen ATX use mosfet here, though the 5V STB supply is usually mosfet driven
Nice, thanks for your explanation
Maybe couple videos about intermittent failures? How to diagnose them, some tips'n tricks.
Hey up nah rich great vid m8 learning all the time 👍antiphase is my word of the week KTF
28:20 You forgot 1uF polypropylene capacitor in series with the winding. This is critical. Actually it holds the charge.
Great teaching..thanks.