Thanks again. I probably wouldn't mess with modifying a supply with multiple secondaries like this because of the single feedback loop. I believe this is the same problem people have when they try to modify a PC power supply as a bench power supply. I don't think most people are trying to mess with the feedback voltage, but most people will eventually place a heavy load on a rail that doesn't have a feedback reference loop(s) and I think that causes problems. So far I've limited my switching supply mods to the most simple off line topologies. I have modified the output of an HP printer power supply though. Those are my favorite because the secondary is a center tapped winding on the older style power bricks. They make a great dual polarity configuration for testing op amps and audio amp circuits. Thanks again Mr G.W. -Jake ;)
Bravo. I love your practical tour of the circuit. You show how knowledge is mightier than fancy equipment. Just be careful poking around those high voltages. You might want to open a Patreon account so viewers can contribute funds to support your explanations. I wouldn't mind donating.
Slowly going through this series as time permits. Its excellent work. What I consider real engineering design considerations and testing. I will try to come up to this level.
The RMS AC mains voltage should be greater than the pulsating DC RMS voltage after the bridge (Off Line converter) by two diode drops with no load or smoothing true RMS. After filtering the RMS will increase relative to the mains having less ripple (moving towards DC). I enjoy watching your analysis, but viewers should be aware that power supply tests for production test are much more rigorous. For example, in doing the percent Load Voltage Regulation measurement you would use an AC power supply that has a controlled regulated AC output, regardless of the slight variations in line voltage or line frequency, commonly called an AC Power supply (also the AC output is isolated from the AC mains input, which is important for operator safety). An AC Power Supply is used because the definition of percent Load Voltage Regulation assumes a constant and stable line (mains) input voltage and frequency. In a sense output loading is done in a similar manner using DC Electronic Load(s) to provide a stable load measuring base (like 50% load current) while you vary the line voltage for percent Line Voltage Regulation. So there are many different categories of power supply tests, most common are; Static Characteristics of Regulated Power Supplies, Dynamic Characteristics of Regulated Power Supplies (which many times includes output impedance and stability), Pre-compliance Testing; Conducted and Radiated EMI and THD, Voltage Regulated Power Supply efficiency, Power Factor, and environmental testing (temperature, humidity, vibration, etc.). There are many more tests but are applicable to different product categories, for example worse case in-rush or surge current. Then after the design is completed the supply has to be tested by a third party lab for official compliance verification.
I give you a thumbs up. Could you please, please make a video about the dummy load you are using it looks self powered and deceptively simple. How is it done?
I was thinking about this one (screenshot of a Texas Instruments TL431 data sheet page) drive.google.com/file/d/1B7-rTZZJBhhhxBIFGl6A5urmRRc-N-Mj/view?usp=drivesdk I've built that one before. It works well.
Hi Danyk, do you still have the welding inverter you made? Any chance of a video of it on how you designed it & its operation, that would be most interesting.
U do have an amazing knowlege of electronics and a great teching method,hats off to you ,plz don't stop and make more and more videos....My request ...Plz do make a video on ur evergreen dc load circuit,awaiting ur response soon
Your Videos are amazing, man! Love the amount of details and explanation. But for your own safety, when your poking around high voltages with your multimeter, you should maybe consider connecting it via your autotransformer/mains isolation transformer. So you can accidentally touch the contacts and still be fine (to live another day and make more great videos).
I have an fsdh321 that in datasheet says 12 volt start voltage. does this mean that lower then 12 volt is not going to start working cause in the pcb that is soldered is working with 9 volt and i cant explain how!
Hey that was a clever way to show the changing schematic, super imposed on the video :-D. But you missed something...... no cat walking by LOL :). Im not sure if the meter reading across the snubber resistor was 100%, unless your meter was able to give true rms at that frequency. Only 13 volts running the pwm, i was conned by the 50 volt capacitor lol. Even a couple of resistors from the +12 and +5v to the tl431 input would not give a perfect regulation, group regulation much like pc power supplys.
I'd normally draw it on a paper, but the paper schematic was a mess already :D. I'm in a different location, that's why no cat. You're right, the capacitor in the snubber is far to low to have pure DC on it. The multimeter was showing an average voltage, not RMS. Low capacity capacitor usualy don't come in low voltage ratings. 50V may be the lowest rating of 10uF. PC power supplies have little better sensing that averages more output voltages. It's a bit more accurate, but no output is really regulated. And there's a common inductor for more outputs.
Thanks for video. Nice vacuum tubes :-) I am very interesting in switching power supplies, But I am still fighting with the high hearable frequencies (about 10 kHz coil whine). Can you, please, make a video, how to solve it in older PSUs?
Very interesting vídeo! O like the old tube oscilloscope! You built the driving circuits? I also have an old oscilloscope tube. Do you have the driving circuits schematics?
hi.... Sir I want to know why the meter show frequency, even the red probe of meter is in air and please make video for measurement of voltage across transformer primary to secondary as per UL950 (Working Voltage Measurement)
new subscriber here.. very nice explanation.. credit to you.. i want to download your videos as my collection for additional knowledge.. ill support your channel keep uploading more.. thanks
It tends to go up with the load. More secondary current means more primary current. More primary current means more overshoots at the primary during the moment when the transistor turns off.
How to modify (lower) output voltage.. can anyone help??.. i tried varying 330ohm (2.2k ohm in my case) resistor connected at optocoupler but that dosent help. No changes in outuot..
Yes, you can put power supplies in parallel, as long as they are the same rated voltage, at the end, the power will sum if they are about the same rated power.
Duly posted this as well at EEVblog (also, I'm trying subtly to get you a good DSO). Brother, if you benefit, then we all do. Keep 'em coming! PS. Your video showed me about exceeding the diode PIV when adjusting the feedback for more V.. pop! ( www.eevblog.com/forum/beginners/fixing-2-small-smps-(for-dual-lm317-split-supply)/ )
It depends on your country, here in Czech Republic we use U for Voltage. Also maybe you can see different drawnings for resistors, capacitors... Yes, there are some differences but it's not important for understanding how things works. ... We also have swapped Y and Z on our pc keyboards and our B guitar chord is 1/2 "tone" lower then it is in some other countries and if I play an "international" B-chord, then I call it H-chord :D
Most greatest video series ive seen in my life.
Thanks again. I probably wouldn't mess with modifying a supply with multiple secondaries like this because of the single feedback loop.
I believe this is the same problem people have when they try to modify a PC power supply as a bench power supply. I don't think most people are trying to mess with the feedback voltage, but most people will eventually place a heavy load on a rail that doesn't have a feedback reference loop(s) and I think that causes problems.
So far I've limited my switching supply mods to the most simple off line topologies. I have modified the output of an HP printer power supply though. Those are my favorite because the secondary is a center tapped winding on the older style power bricks. They make a great dual polarity configuration for testing op amps and audio amp circuits.
Thanks again Mr G.W.
-Jake
;)
Fantastic quality teaching. Thank you for your time and dedication.
Bravo. I love your practical tour of the circuit. You show how knowledge is mightier than fancy equipment. Just be careful poking around those high voltages.
You might want to open a Patreon account so viewers can contribute funds to support your explanations. I wouldn't mind donating.
Best Engineer ever seen, Tks alot dear, Keep in touch. congratulaations from Alexandria - Egypt
Slowly going through this series as time permits. Its excellent work. What I consider real engineering design considerations and testing. I will try to come up to this level.
Very, well explained detailed and professionally presented..GREAT WORK..!!
Really this is the best way of explaining how to measure directly on a board.thank you sir .good work
thank you so much for your measurement video I found that and your other videos so helpful to learn how to fault find in a methodical way
The RMS AC mains voltage should be greater than the pulsating DC RMS voltage after the bridge (Off Line converter) by two diode drops with no load or smoothing true RMS. After filtering the RMS will increase relative to the mains having less ripple (moving towards DC).
I enjoy watching your analysis, but viewers should be aware that power supply tests for production test are much more rigorous. For example, in doing the percent Load Voltage Regulation measurement you would use an AC power supply that has a controlled regulated AC output, regardless of the slight variations in line voltage or line frequency, commonly called an AC Power supply (also the AC output is isolated from the AC mains input, which is important for operator safety). An AC Power Supply is used because the definition of percent Load Voltage Regulation assumes a constant and stable line (mains) input voltage and frequency. In a sense output loading is done in a similar manner using DC Electronic Load(s) to provide a stable load measuring base (like 50% load current) while you vary the line voltage for percent Line Voltage Regulation.
So there are many different categories of power supply tests, most common are; Static Characteristics of Regulated Power Supplies, Dynamic Characteristics of Regulated Power Supplies (which many times includes output impedance and stability), Pre-compliance Testing; Conducted and Radiated EMI and THD, Voltage Regulated Power Supply efficiency, Power Factor, and environmental testing (temperature, humidity, vibration, etc.). There are many more tests but are applicable to different product categories, for example worse case in-rush or surge current. Then after the design is completed the supply has to be tested by a third party lab for official compliance verification.
I give you a thumbs up. Could you please, please make a video about the dummy load you are using it looks self powered and deceptively simple. How is it done?
I was thinking about this one (screenshot of a Texas Instruments TL431 data sheet page)
drive.google.com/file/d/1B7-rTZZJBhhhxBIFGl6A5urmRRc-N-Mj/view?usp=drivesdk
I've built that one before. It works well.
ربنا يبارك فيك
دائما شروحاتك جميله و تبذل بها جهد
Hi Danyk, do you still have the welding inverter you made?
Any chance of a video of it on how you designed it & its operation, that would be most interesting.
Whatching the video i must tell my self repeatedly to stop trying to understand what's going on and just whatch!
🙏🏼
I am from India u are great teacher
U do have an amazing knowlege of electronics and a great teching method,hats off to you ,plz don't stop and make more and more videos....My request ...Plz do make a video on ur evergreen dc load circuit,awaiting ur response soon
You are a real master sir love from india
9:21 Why doesn't the snubber clamp eliminate the oscillation? Aren't those undershoots a problem?
In my time we were adding linear voltage r.egulator on the auxiliary output, the = and - minus output here!
Sir you are excellent.
When measuring frequency with a multimeter,put a capacitor in series with its cables(probes),so you can measure accurately.
A clear explanation! Thank you.
Thank you very much for your video so this is very usefull for me..Good luck your tecnical videos...
inspired by your work, Thanks and keep them coming
Your Videos are amazing, man! Love the amount of details and explanation. But for your own safety, when your poking around high voltages with your multimeter, you should maybe consider connecting it via your autotransformer/mains isolation transformer. So you can accidentally touch the contacts and still be fine (to live another day and make more great videos).
Thanks :)
I'm not touching anything grounded, just for case :)
Excellent teaching services
I like
4:26 the only guy that draws letter A as a among US character
You could activate the subtitles to be able to follow his impressive explanations. Many thanks.
Is there a video where the circuitry of the variable load gadget is described?
Never seen vids, like dis !!!!! So amazing explanation of PSU
Very much helpful.thanks.
how did you determine the polarity of the pulse/flyback transformer??
As always - excellent!
I have an fsdh321 that in datasheet says 12 volt start voltage. does this mean that lower then 12 volt is not going to start working cause in the pcb that is soldered is working with 9 volt and i cant explain how!
What is the purpose of capacitor (1nF) above opto-coupler, connected between primary and secondary winding?
EMI compliance
Champagne is very dangerous for satelite receiver.....yesterday i have accidentally distroyed my sat receiver can îți be repaired?
Video well done, congratulations, good work.
excellent analysed.
Super. Useful video impro others. I just understand. Thanks sir
When working are just measuring on the hot side of a power supply the use of an isolation transformer is mandatory.
Why come?
Hey that was a clever way to show the changing schematic, super imposed on the video :-D.
But you missed something...... no cat walking by LOL :).
Im not sure if the meter reading across the snubber resistor was 100%, unless your meter was able to give true rms at that frequency.
Only 13 volts running the pwm, i was conned by the 50 volt capacitor lol.
Even a couple of resistors from the +12 and +5v to the tl431 input would not give a perfect regulation, group regulation much like pc power supplys.
I'd normally draw it on a paper, but the paper schematic was a mess already :D. I'm in a different location, that's why no cat. You're right, the capacitor in the snubber is far to low to have pure DC on it. The multimeter was showing an average voltage, not RMS. Low capacity capacitor usualy don't come in low voltage ratings. 50V may be the lowest rating of 10uF. PC power supplies have little better sensing that averages more output voltages. It's a bit more accurate, but no output is really regulated. And there's a common inductor for more outputs.
Thanks for video. Nice vacuum tubes :-)
I am very interesting in switching power supplies, But I am still fighting with the high hearable frequencies (about 10 kHz coil whine). Can you, please, make a video, how to solve it in older PSUs?
thanks for the education!
I have a 12V output that I needed to change to 14V, how to calculate the sensing resistor?
Nice video
Fantastic but i am confused on resitor wattage of startup and snubber register.
Very interesting vídeo!
O like the old tube oscilloscope!
You built the driving circuits? I also have an old oscilloscope tube. Do you have the driving circuits schematics?
Thanks :)
My DIY scope is documented on this webpage:
danyk.cz/osc_en.html
hi.... Sir I want to know why the meter show frequency, even the red probe of meter is in air and please make video for measurement of voltage across transformer primary to secondary as per UL950 (Working Voltage Measurement)
Sir, Is there vedio made by you on lg make adaptor 19vots, 2.1 amp
wow, thank you! that was impressive!
You can activate the video subtitles?. Thank you
new subscriber here.. very nice explanation.. credit to you.. i want to download your videos as my collection for additional knowledge..
ill support your channel keep uploading more..
thanks
Dear which multimeter you are using?
Please tell me the brand and model. I wanna buy...
Thanks
MY-68 Digital Multimeter
Does the energy dissipated by the primary snubber change depending on load?
It tends to go up with the load. More secondary current means more primary current. More primary current means more overshoots at the primary during the moment when the transistor turns off.
Do you have Telegram because I want to ask some questions about the diagram of Power Supply
Hey man how can I design and build SMPS of required power of my own
👍🏻👍🏻👍🏻
🙏🏼
You are awesome!
How to modify (lower) output voltage.. can anyone help??.. i tried varying 330ohm (2.2k ohm in my case) resistor connected at optocoupler but that dosent help. No changes in outuot..
Nice! really nice! Thanks!
Why is there an 1 nF capacitor between live and output?
To prevent a high frequency noise (interference) at the output.
8:40 never seen such oscillator
can you do the TV power supply explanation with readings. would be much more helpfull.
ThanK you very much for your video.
Excellent
can i bring 2 Switching power supplys in parallel ? yes? how do i do it? i want to use it for ZVS
Yes, you can put power supplies in parallel, as long as they are the same rated voltage, at the end, the power will sum if they are about the same rated power.
Duly posted this as well at EEVblog (also, I'm trying subtly to get you a good DSO). Brother, if you benefit, then we all do. Keep 'em coming! PS. Your video showed me about exceeding the diode PIV when adjusting the feedback for more V.. pop! ( www.eevblog.com/forum/beginners/fixing-2-small-smps-(for-dual-lm317-split-supply)/ )
Thanks
Please make video's on smps battery charger 20 amp.
Excellent shame on those thumbs downers!
Great Teacher and great videos. One thing though!. I=V/R. That's V (veeee) not U (you). Just for your information.
It depends on your country, here in Czech Republic we use U for Voltage. Also maybe you can see different drawnings for resistors, capacitors... Yes, there are some differences but it's not important for understanding how things works.
... We also have swapped Y and Z on our pc keyboards and our B guitar chord is 1/2 "tone" lower then it is in some other countries and if I play an "international" B-chord, then I call it H-chord :D
@@Voldees Thanks for pointing that out. I didn't know that.
I stand corrected.
@@MrLRankin2 In Poland also U for voltage and so on... ;)
In what country is U the Voltage?
Late but...
For example in Poland we use U for voltage
Czech Republic
How to make 1.5vDC inverter to 220vAC
0:40 um
excelente amigo
tnxboss
You made a mistake when calculating the power dissipation of the resistors in the snuber network.
you re great
Two 120K ohms snubber resistors in parallel... makes it 60K ohms!
you were wrong when you measured the current consumption of the chip because that 100 ohms resistor sees AC current and not DC !
Hello DiodesGoneWild, you are absolutely amazing. Do you have a modern scope? If not, maybe we start a go fund me campaign for a Rigol DS1054Z?
Thanks :) I have no modern scope...
🙏👍
Pls make it
nixie tube sent me back to 1975
ubiquiti power adaptor..........
V=IR not U
U for voltage for example in Poland, then it's O.K. for me ;)
Tyo thyere
You are an inspriration.
First my dude
When measuring frequency with a multimeter,put a capacitor in series with its cables(probes),so you can measure accurately.
Excellent teaching services
I like
When measuring frequency with a multimeter,put a capacitor in series with its cables(probes),so you can measure accurately.
Hello sir,can u make a demo video ar share any link regarding fequency measurements using multimeter..
Tks,Regards