Honestly, I have asked at least 50 engineers and professors, "How does a modern charger/adapter work? Why is it so much lighter than the old ones? How does it cool down after fully charging the battery? " Surprisingly, not a single one could answer. As if they have never learned how SMPS works. Then I had to tell them how it works. You are the first one who explained it correctly and simply, plus added a few things more than I knew. Thank you. I hope you get a million subscribers. Then next time, please show the inside of a a broken (old) charger/adapter to make it even more exciting. If I could give you 5 star rating, I would have given you 7 stars.
Good explanation, but with a few faults, which I point out below: 1. The full wave bridge rectifier does not 'eliminate' the negative half cycle of the supplied 220v power as described but it 'inverts' it so that both half cycles are now positive. A half wave rectifier would have eliminated the negative half cycle resulting in more output voltage ripple and a bigger capacitor to smooth out the ripple. 2. The electrical efficiency of circuit is primarily because the 7805 regulator in the conventional circuit is in fact a power dissipating series resistance conducting the main load current that wastes power. 3. Another primary advantage of the high frequency convertor, is as described, the elimination of the LARGE and HEAVY low frequency voltage step down transformer with silicon steel laminations with a small high frequency transformer made of a ferrite powder core reduces power dissipation. While the small size results from the high frequency as described, the increased efficiency however results primarily from the replacement of the conventional series regulator by the feedback circuit operating at high frequency.
Good explanation. Just one small correction at 6:14 , that 100kHz output from converter circuit is DC supply only. The transformer is able to work because it is a pulsed DC of high frequency that avoids core saturation. I have seen many people calling it as several kHz AC supply but it's pulsating DC. Overall, a good video 👍
It's the BEST explanation I've seen. I loved the way you explained it step by step AND built up the circuit diagram step-by-step. Having the entire diagram to start off causes confusion.
From the input to the output part of the explanation plus the professional illustration of the schematic is really awesome. You are an exelent teacher. Keep It Up. Thanks and more power to you.
In converters that use an integrated circuit for control the auxiliary winding is normally used to provide power for the IC. The IC can start up through a high-value resistor from the rectified AC input, but it would waste a lot of power to keep the IC going that way. Once switching starts the aux winding keeps the control IC powered. These self-oscillating circuits aren't common in better quality products because they don't perform as well. Their real advantage is that they are cheap and simple.
I search this type of knowledgeable video about how circuit perform any action. I can't find and lastly I found this one but some video post on this channel related to this I expect more to understand all types of circuit easily about how the circuit work.
WONDER SIR ONLY FEW CAN MOULD OVER MANY COULD MAKE EVICT THE THIRSTY LEARNERS....OUR BLESSINGS, IF WE THE INDIANS LISTEN SUCH LECTURES MAKE IN INDIA WOULD NOT BE A DREAM.......
Thanks for your explanation, very clear and easy to understand, I hope you'll make more videos like this, and basic electronics. More 'amps' to your channel.
Thank you so much for this video. Very informative and more than that very very in depth , accurate and very well analyzed . One question : what is the usage of the resistor connected in parallel , just under the zener diode . and why parallel not in series . Thank you again .
If you analyze closely, then the 100 Ω, resistor is in SERIES with the zener diode. It limits the current flow through it. The zener is marked 4.2VZ. The other diode in the bottom you see is the opto-coupler LED. However, this LED is fabricated inside a 5 or 6 pin package. The LED's forward bias drop of 0.8V (typically), is visible across the 100 Ω resistance as well. This in turn lifts the -ve potential point of zener by 0.8V, thereby adding up to the zener breakdown voltage (in this case 4.2V). Hence output Vo now becomes 4.2V + 0.8V = 5.0V. Hope you understand it now.
@@fbxlearning8725 That resistor doesn't do so much limiting of the zener current as much as it shunts zener current away from the opto-coupler. If the zener current got too high, the optocoupler LED would burn above 50-60mA. Since the OC LED is in parallel with the resistor, this resistor actually INCREASES the zener current (due to decreased total series resistance.
Very nice explanation. One thing you forget to tell. The capacitor value near T13001 Transistor. You have written it there but it is not clear and can't be read. Please specify. Thank you very much.
This circuit needs a good transformer that does not saturate over high frequency and current. A special attention is needed over Foucault currents on high frequencies too.
Good explanation. So if you *double* the secondary voltage and *change the zener* to 18.2 volts you can convert this circuit for use as a miniature _laptop_ charger.
😃 Absolutely. You got the point. Play around with secondary voltage and zener values and get any desired output. But there is a catch. The amount of current that you can draw out of this circuit. Laptop charger needs more current (rather a steady current). I did not touch on that part yet. Probably left it for some other discussion.
Very Nice explanation sir. First secondary you mention is auxiliary winding i think. Please make video on working of 50w LED Driver/power supply circuit, constant current, primary side regulation without optocoupler and with IC. Thank you in advance.
Yep, you are correct. First secondary is the auxiliary, ancillary, subservient, subsidiary. Choose a way you want, to describe the behavior :-) We will follow up this request. Ok, we will create in a separate video to explain operation of SMPS regulation without feeback opto-coupler. Just to brief you quickly, the switching mechanism remains the same, but APPROXIMATE regulation happens at the primary. The N1:N2 coil ratio does the rest at secondary. Thanks for your feedback & suggestion.
So there was already a part that keep chopping off current to make faster pulses upto 100Khz before the last part of opto start to cut off overload current/voltage? 🤷♂️ I think this is one of the best in-schematic explanation for phone charger 😂 Although constructing one could be way more trouble. Ex : where is the part of canceling EMC from input? Or the polarized capacitor was already enough to filter that ?
A small correction is required. The output voltage is shown as 10V but the Zener voltage 4.2V plus photocoupler diode voltage add up to 5V so the output voltage should be 5V. Perhaps you meant 10V is the maximum voltage with feedback removed but should be explained.
thank you sir you are awesome. one's again sir. please sir I want to learn more about the transformer coiling. the position of the coiling. positive and negative of the transformer. starting of the primary. starting of the auxiliary. nd the secondary. please sir am having this problem help me out sir thank you nd God bless you.
Very helpful video for me as a student . But sir,,, Is this type of Small and modern transformer is available in "open electronics market" to buy separately ?
Kindly explain the purpose of aux winding. We could have got fill base current by reducing value of high value resistor. Secondly , why we have put a capacitor between aux winding and base of main transistor. If the capacitor is fully charged, it will not allow aux current to pass through it. Kindly clarify.
[FBX]: Yes logically it is correct to reduce the high resistance to feed more current to the main transistor. But then we need to design another mechanism to CONTINUOUSLY modulate the resistance value high & low at over 100KHz speed. This may not be a very easy task (without an external controller). & the controller itself would need 3.3/5V to run. It will defy the whole purpose of power supply design. If you have any other design in mind that can switch a resistance high & low to regulate the current, then please let us know. We would be happy & excited to analyze it further. [FBX]: You are correct, if the capacitor charges to the max, then then there wont be any current. In fact, the series circuit of a resistance and capacitance acts as delay logic. Understand it this way, the main BJT stays in the amplification area till it receives more current to move to saturation. The amount of time it stays in the amplification area (before reaching saturation) is controlled by the RC network. Hope this clarifies.
Hello sir, excellent explanation. There's just one thing bugging me what is the reason for placing a 100 ohm resistor in parallel to the optocoupler diode?
We have one more theory. When the main transistor reaches saturation stage, the current is no more changing and so voltage across windings is dropped to zero and again the cycle repeats. So which theory is responsible for making oscillation. Yours or this. Kindly explain.
[FBX]: The oscillation theory is the same. The main BJT once in saturation, now needs to turn off. The secondary BJT helps in doing this by turning itself ON & flushing out the change from main BJT base. Hope this explains.
It is Alternating Current (AC). The wave is of pulsating type. Somewhat like a square waveform. A square wave has 50% duty cycle, whereas a pulsating value has comparatively lesser duty cycle. Let me try to explain you here a bit. You usually might have visualize a sinusoidal wave as a AC. But any repeated signal can be considered as an AC. The duration of the repetition decides the frequency. However, a pulsing waveform is a mix of many many (almost infinite frequencies), because of very high di/dt and dv/dt factors. More explanation in Fourier analysis.
![[UNCUT] “อภิสิทธิ์” ครม.อุ๊งอิ๊ง แย่งเก้าอี้กันฝุ่นตลบ “ทักษิณ” บงการเอง Iคนดังนั่งเคลียร์I 21ส.ค.67](http://i.ytimg.com/vi/a_b-kItw2jY/mqdefault.jpg)
Honestly, I have asked at least 50 engineers and professors, "How does a modern charger/adapter work? Why is it so much lighter than the old ones? How does it cool down after fully charging the battery? " Surprisingly, not a single one could answer. As if they have never learned how SMPS works. Then I had to tell them how it works. You are the first one who explained it correctly and simply, plus added a few things more than I knew. Thank you.
I hope you get a million subscribers. Then next time, please show the inside of a a broken (old) charger/adapter to make it even more exciting. If I could give you 5 star rating, I would have given you 7 stars.
That was the best explanation of a high frequency smps supply I’ve ever seen. Tyvm. Your a great teacher.
Finally, someone explained in detail the purpose of this connection and how to make pulses with transformer and transistor.
Good explanation, but with a few faults, which I point out below:
1. The full wave bridge rectifier does not 'eliminate' the negative half cycle of the supplied 220v power as described but it 'inverts' it so that both half cycles are now positive. A half wave rectifier would have eliminated the negative half cycle resulting in more output voltage ripple and a bigger capacitor to smooth out the ripple.
2. The electrical efficiency of circuit is primarily because the 7805 regulator in the conventional circuit is in fact a power dissipating series resistance conducting the main load current that wastes power.
3. Another primary advantage of the high frequency convertor, is as described, the elimination of the LARGE and HEAVY low frequency voltage step down transformer with silicon steel laminations with a small high frequency transformer made of a ferrite powder core reduces power dissipation.
While the small size results from the high frequency as described, the increased efficiency however results primarily from the replacement of the conventional series regulator by the feedback circuit operating at high frequency.
bro, I want to ask, is the current coming out of the base a negative current?
Good explanation. Just one small correction at 6:14 , that 100kHz output from converter circuit is DC supply only. The transformer is able to work because it is a pulsed DC of high frequency that avoids core saturation. I have seen many people calling it as several kHz AC supply but it's pulsating DC. Overall, a good video 👍
Finally I understand the works behind this circuit. Thank you teacher.
It's the BEST explanation I've seen. I loved the way you explained it step by step AND built up the circuit diagram step-by-step. Having the entire diagram to start off causes confusion.
Give me a better understanding of an sm c circuit. Many thanks, section by section description is very helpful.
From the input to the output part of the explanation plus the professional illustration of the schematic is really awesome. You are an exelent teacher. Keep It Up. Thanks and more power to you.
excellent video from FBX Learing and Haseeb Electronics. i am really greatfull to you both.
Actually, this is the best explanation i have ever come across in terms of the working principle of phone charger.
Well done, Bravo dude💪
This is best explanation I have got on the concept. Thanks a lot looking for more stuffs from you and your crew you guys are great.,💯💕
this was great I never understood the purpose of the auxiliary winding. now I have a much better idea.
In converters that use an integrated circuit for control the auxiliary winding is normally used to provide power for the IC. The IC can start up through a high-value resistor from the rectified AC input, but it would waste a lot of power to keep the IC going that way. Once switching starts the aux winding keeps the control IC powered.
These self-oscillating circuits aren't common in better quality products because they don't perform as well. Their real advantage is that they are cheap and simple.
The best teacher nice explanation sir
Very good and understanding. It is helpful for my engineering project.
Great to hear!
Detaiyed and wonderful explanation, thank you from Turkey.
The world's best teacher thanks
I search this type of knowledgeable video about how circuit perform any action. I can't find and lastly I found this one but some video post on this channel related to this I expect more to understand all types of circuit easily about how the circuit work.
It is indeed an Excellent Vlog about SMPS
Way of teaching is excellent
You should do more videos like this. Excellent explanation.
More to come! You can suggest us, as well !!!
Best explaination ever....
My students will love you bro....
Please help us with signal amplification in a clap switch sir we really appreciate your work
Great video.
Very well explained , appreciate your effort , keep making more such informative videos - thanks a lot !
Good explanation...expecting more..
Sure 👍
Supper .... explained well.....expect more vediods....👍👍👍
WONDER SIR ONLY FEW CAN MOULD OVER MANY COULD MAKE EVICT THE THIRSTY LEARNERS....OUR BLESSINGS, IF WE THE INDIANS LISTEN SUCH LECTURES MAKE IN INDIA WOULD NOT BE A DREAM.......
Very useful and informative.. thank you
🙏🌾💓very nice teach sirji valubal lesson continue sir poor stundent new electronic fild nice help🙏🙏
Thanks for your explanation, very clear and easy to understand, I hope you'll make more videos like this, and basic electronics. More 'amps' to your channel.
very clearly explanation,good teacher.
Very nice explanation, thanks sir
tq sir.. you are a great teacher,
Very good explanation & clearly I am understanding .Thanks
Wow this is a very nice technical educational video...thank u very much
Very informative sir. Thank you 🙏
in depth explanation. Also, nicely explained.
Thank you sir for the good explanation.
This was gold! Thank you for being a great teacher.
Much appreciated sir. Thanks a lot for very good explaining sir
Nice video tutorial on how smps works. More power
Very good information
This is a great video for smps beginners. Hope you intend to go further on smps
Very useful video sir....and. Good explanation
Thank you so much for this video. Very informative and more than that very very in depth , accurate and very well analyzed . One question : what is the usage of the resistor connected in parallel , just under the zener diode . and why parallel not in series . Thank you again .
If you analyze closely, then the 100 Ω, resistor is in SERIES with the zener diode. It limits the current flow through it. The zener is marked 4.2VZ. The other diode in the bottom you see is the opto-coupler LED. However, this LED is fabricated inside a 5 or 6 pin package. The LED's forward bias drop of 0.8V (typically), is visible across the 100 Ω resistance as well. This in turn lifts the -ve potential point of zener by 0.8V, thereby adding up to the zener breakdown voltage (in this case 4.2V). Hence output Vo now becomes 4.2V + 0.8V = 5.0V.
Hope you understand it now.
@@fbxlearning8725 Thank you so much for your reply . I think I need to study and concentrate more on the issue .
@@fbxlearning8725 That resistor doesn't do so much limiting of the zener current as much as it shunts zener current away from the opto-coupler. If the zener current got too high, the optocoupler LED would burn above 50-60mA.
Since the OC LED is in parallel with the resistor, this resistor actually INCREASES the zener current (due to decreased total series resistance.
Very useful & knowledgeable information
Nice explanation .Thanks sir.
Thank you very much,but is it ok to use a transistor instead optcoupler, and what determines the frequency of the oscillator circuit please
you are the best
big thanks from Iraq
Very nice explanation. One thing you forget to tell. The capacitor value near T13001 Transistor. You have written it there but it is not clear and can't be read. Please specify. Thank you very much.
Bravo🎉👏👏
Happy new year 2021
Thank you! You too!
@@fbxlearning8725 🙏
Nice Explained
Good way of explanation
Please continue sir
Glad you got interested.
YOU SIR MADE ELECTRONIC SIMPLE AND INTRESTING THANKS 😊
This circuit needs a good transformer that does not saturate over high frequency and current. A special attention is needed over Foucault currents on high frequencies too.
Yes true. I will publish a page or video to explain the calculations involved in designing the flyback transformer.
Thank you for this vidéo, good explain to this circuit.
Good job
Very nice
Good. Thanks 🙏🙏🙏🙏🙏
Deserve a Like & Subs
Best explanation sir
Thank you very much
Best video , thank you.
Good explanation. So if you *double* the secondary voltage and *change the zener* to 18.2 volts you can convert this circuit for use as a miniature _laptop_ charger.
😃 Absolutely. You got the point. Play around with secondary voltage and zener values and get any desired output. But there is a catch. The amount of current that you can draw out of this circuit. Laptop charger needs more current (rather a steady current). I did not touch on that part yet. Probably left it for some other discussion.
You would need a much more powerful input transistor and output diode(s), plus a larger transformer and output capacitor.
Thanks for your 6v or 5v smps circuit I got more knowledge please give me the details of components in13003flyback aera
Excellent video...Be Blessed🎉
Very cool, much more efficient I think with my limited understanding.
Very good explanation ! Thank you.
Very Nice explanation sir. First secondary you mention is auxiliary winding i think. Please make video on working of 50w LED Driver/power supply circuit, constant current, primary side regulation without optocoupler and with IC. Thank you in advance.
Yep, you are correct. First secondary is the auxiliary, ancillary, subservient, subsidiary. Choose a way you want, to describe the behavior :-)
We will follow up this request. Ok, we will create in a separate video to explain operation of SMPS regulation without feeback opto-coupler. Just to brief you quickly, the switching mechanism remains the same, but APPROXIMATE regulation happens at the primary. The N1:N2 coil ratio does the rest at secondary.
Thanks for your feedback & suggestion.
Very very nice explain
So there was already a part that keep chopping off current to make faster pulses upto 100Khz before the last part of opto start to cut off overload current/voltage? 🤷♂️
I think this is one of the best in-schematic explanation for phone charger 😂
Although constructing one could be way more trouble. Ex : where is the part of canceling EMC from input? Or the polarized capacitor was already enough to filter that ?
Love your explanation thanks
you've earned yourself a subscriber!
Very good video.
Please make one video explaining how should we pick values for our components when designing our own circuit.
Very clear. Thanks
Nice video, thanks for sharing, like it :)
Excellent explanation
A small correction is required. The output voltage is shown as 10V but the Zener voltage 4.2V plus photocoupler diode voltage add up to 5V so the output voltage should be 5V. Perhaps you meant 10V is the maximum voltage with feedback removed but should be explained.
bro, I want to ask, is the current coming out of the base a negative current?
thank you sir you are awesome. one's again sir. please sir I want to learn more about the transformer coiling. the position of the coiling. positive and negative of the transformer. starting of the primary. starting of the auxiliary. nd the secondary. please sir am having this problem help me out sir thank you nd God bless you.
This is veyr good !!! Thankyou for the explanation ❤
Glad it was helpful!
Very helpful video for me as a student . But sir,,, Is this type of Small and modern transformer is available in "open electronics market" to buy separately ?
Спасибо за объяснение!
U are a gd teacher.
Pls can I get 50v/2A from this type of SMPS.If so,how.
Tnx.
one of the explanation ive seen
Kindly explain the purpose of aux winding. We could have got fill base current by reducing value of high value resistor. Secondly , why we have put a capacitor between aux winding and base of main transistor. If the capacitor is fully charged, it will not allow aux current to pass through it. Kindly clarify.
[FBX]: Yes logically it is correct to reduce the high resistance to feed more current to the main transistor.
But then we need to design another mechanism to CONTINUOUSLY modulate the resistance value high & low at over 100KHz speed. This may not be a very easy task (without an external controller).
& the controller itself would need 3.3/5V to run.
It will defy the whole purpose of power supply design.
If you have any other design in mind that can switch a resistance high & low to regulate the current, then please let us know.
We would be happy & excited to analyze it further.
[FBX]: You are correct, if the capacitor charges to the max, then then there wont be any current.
In fact, the series circuit of a resistance and capacitance acts as delay logic.
Understand it this way, the main BJT stays in the amplification area till it receives more current to move to saturation.
The amount of time it stays in the amplification area (before reaching saturation) is controlled by the RC network.
Hope this clarifies.
@@fbxlearning8725 thx for clarification.
@@fbxlearning8725 it means , r C values are such choose to keep to keep the bjt in active status.
Thankyou so much sir🙏🙏
very nice
bravo bravo ..........
Nice video
good video
Hello sir, excellent explanation. There's just one thing bugging me what is the reason for placing a 100 ohm resistor in parallel to the optocoupler diode?
It limits the current flow through the zener.
We have one more theory. When the main transistor reaches saturation stage, the current is no more changing and so voltage across windings is dropped to zero and again the cycle repeats. So which theory is responsible for making oscillation. Yours or this. Kindly explain.
[FBX]: The oscillation theory is the same.
The main BJT once in saturation, now needs to turn off.
The secondary BJT helps in doing this by turning itself ON & flushing out the change from main BJT base.
Hope this explains.
@@fbxlearning8725 Is on and off ,,, of both transistors rely on capacitors charging and discharging ? Kindly explain....
Very good, comrade!
Glad to hear from you.
sir can you make video on electric arc
Surely. But I need to workout on it, a bit.
Great job, thanks
17:33 see
Not quite clear with your question. Please elaborate.
Supper 😁😁👍class
12:40 is that DC or AC curent going to the transformer?
It is Alternating Current (AC). The wave is of pulsating type. Somewhat like a square waveform. A square wave has 50% duty cycle, whereas a pulsating value has comparatively lesser duty cycle. Let me try to explain you here a bit. You usually might have visualize a sinusoidal wave as a AC. But any repeated signal can be considered as an AC. The duration of the repetition decides the frequency.
However, a pulsing waveform is a mix of many many (almost infinite frequencies), because of very high di/dt and dv/dt factors. More explanation in Fourier analysis.
Sit, why the current from the winding can be pass the capasitor and triggered the basis of the transiator? Thx