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.
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.
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.
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.
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.
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 👍
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.
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.
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.
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.
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.
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?
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.
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.
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.
I did not touch base on the fuse requirement and design. Because it need a detailed explanation and I kept it for another session. For now. the fuse rating depends on the Operating Current. The current rating of a fuse is typically de-rated 25% for operation at 25ºC to avoid nuisance blowing. For example, a fuse with a current rating of 10A is not usually recommended for operation at more than 7.5A in a 25ºC ambient. Moreover, the fuse rating is decided by load current as well.
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 ?
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.
The world's best teacher thanks
excellent video from FBX Learing and Haseeb Electronics. i am really greatfull to you both.
Give me a better understanding of an sm c circuit. Many thanks, section by section description is very helpful.
Finally I understand the works behind this circuit. Thank you teacher.
It is indeed an Excellent Vlog about SMPS
Best explaination ever....
My students will love you bro....
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?
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.
Way of teaching is excellent
Very useful and informative.. thank you
Detaiyed and wonderful explanation, thank you from Turkey.
The best teacher nice explanation sir
Very good and understanding. It is helpful for my engineering project.
Great to hear!
You should do more videos like this. Excellent explanation.
More to come! You can suggest us, as well !!!
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.
Good explanation...expecting more..
Sure 👍
Supper .... explained well.....expect more vediods....👍👍👍
Actually, this is the best explanation i have ever come across in terms of the working principle of phone charger.
Well done, Bravo dude💪
Nice video tutorial on how smps works. More power
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.
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 gold! Thank you for being a great teacher.
very clearly explanation,good teacher.
in depth explanation. Also, nicely explained.
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.
you are the best
big thanks from Iraq
Wow this is a very nice technical educational video...thank u very much
Very well explained , appreciate your effort , keep making more such informative videos - thanks a lot !
Very useful video sir....and. Good explanation
Very good explanation & clearly I am understanding .Thanks
Very nice explanation, thanks sir
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 informative sir. Thank you 🙏
Very useful & knowledgeable information
🙏🌾💓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.
Much appreciated sir. Thanks a lot for very good explaining sir
Excellent way of teaching
This is a great video for smps beginners. Hope you intend to go further on smps
Good way of explanation
Please continue sir
Glad you got interested.
Nice explanation .Thanks sir.
tq sir.. you are a great teacher,
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 👍
Excellent video...Be Blessed🎉
Please help us with signal amplification in a clap switch sir we really appreciate your work
YOU SIR MADE ELECTRONIC SIMPLE AND INTRESTING THANKS 😊
Great video.
Thank you sir for the good explanation.
Very good explanation ! Thank you.
you've earned yourself a subscriber!
Best explanation sir
Thank you for this vidéo, good explain to this circuit.
Good job
This is veyr good !!! Thankyou for the explanation ❤
Glad it was helpful!
Love your explanation thanks
Bravo🎉👏👏
Happy new year 2021
Thank you! You too!
@@fbxlearning8725 🙏
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 cool, much more efficient I think with my limited understanding.
Very very nice explain
Very good information
Nice Explained
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.
Good. Thanks 🙏🙏🙏🙏🙏
Nice video, thanks for sharing, like it :)
Excellent explanation
Very good video.
Best video , thank you.
Great job, thanks
Very good, comrade!
Glad to hear from you.
Спасибо за объяснение!
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.
Supper 😁😁👍class
Deserve a Like & Subs
Thanks for your 6v or 5v smps circuit I got more knowledge please give me the details of components in13003flyback aera
Thank you very much
Very clear. Thanks
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.
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.
Thankyou so much sir🙏🙏
Very nice
Please make one video explaining how should we pick values for our components when designing our own circuit.
Thank you very much,but is it ok to use a transistor instead optcoupler, and what determines the frequency of the oscillator circuit please
U are a gd teacher.
Pls can I get 50v/2A from this type of SMPS.If so,how.
Tnx.
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.
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.
Thank you so much.
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 ?
Sit, why the current from the winding can be pass the capasitor and triggered the basis of the transiator? Thx
one of the explanation ive seen
Already clarified. Thx
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.
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.
Pulsating DC, which induce emf in secondary coil. Not ac current, if ac voltage means it should have + ve and -ve wave pulses. Pl don't get confused.
bravo bravo ..........
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?
A nice concept sir, a small doubt wt is the fuse rating
I did not touch base on the fuse requirement and design. Because it need a detailed explanation and I kept it for another session. For now. the fuse rating depends on the Operating Current. The current rating of a fuse is typically de-rated 25% for operation at 25ºC to avoid nuisance blowing. For example, a fuse with a current rating of 10A is not usually recommended for operation at more than 7.5A in a 25ºC ambient. Moreover, the fuse rating is decided by load current as well.
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 ?
bro, I want to ask, is the current coming out of the base a negative current?
Thanks a lot , if this circuit had snubber , was better.