12V 0.6A flyback power supply (with schematic & waveforms)
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- Опубликовано: 5 фев 2022
- What's inside a 12V 600mA 7.2VA flyback switching power supply (SMPS), including its full schematic, how does it work and oscilloscope waveforms.
This power supply came with this 4x AA/AAA NiMH/NiCd charger:
• Weird NiMH/NiCd charge...
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I'll never get tired of your cat interjecting in these videos. 😺
Finally a cheap power supply that is not dodgy, but actually very good, even for it being made down to a price point. Other manufacturers should make them to the same standard.
He didn't even open up the transformer, also I wouldn't call it good for running in DCM
Refreshing indeed! Inexpensive, but not cheap. It even has a low value resistor in series with the auxiliary rectification diode to protect the bootstrap capacitors in the auxiliary supply. Usually, that's not there and it grossly exceeds the ripple current ratings at start-up, and the thing ends up in a landfill in six months after the little cap dries out or bulges. I did the same thing in an SMPS I made for myself, but I think that's the first time I've seen a commercial supply in a tear down with it. It's probably a common feature in reputable supplies, but most of these things are built down to cost oblivion.
Power supply videos are always welcome on this channel.
Thank you Danny. It would be interesting if you could discuss the differences between some of the power supply topologies such as fly back compared to other types. Great informative video👍
We love your presentation style, pronounciation, the way you torture these devices and offcourse your cute cat.
I bought one charger as this, about 12 years ago. It still works/uses (sold at that time) a linear power supply, a heavier “brick” wall power adapter, with those low frequency ferromagnetic transformers, rectifier and capacitive filtering - that is it. Voltage was manually selected, “of course” ;-))
I’m curious to see your other video about the Charger section - I saw now you had already posted it.
Thanks for sharing!
Good to show the output ripple, thanks!
I’m curious what the output ripple of those USB chargers will be and if there are significant differences between them.
Thanks for your always very informative and interesting videos! PS. I hope your sense of smell coming back.
Today i learn more about the tl431 and those resistors, never really know exactly how they work. Thanks for you wonderful explanation
Love your schematics! They are very professional and very helpful! Especially your explanation keep it up!
Every chance I get to snatch up a name brand power supply, I jump on it. Big companies are scared of being sued.
The other day, I found 2 Motorola cable modems someone was throwing out, complete with 12V 1A adapters. Grabbed the power supplies and left the modems for the recycling truck.
Great dissection and explanation video.....many thanks, DGW!
Can we appreciate the entertaining video this man is making while having corona, he has a willpower over 9000!!
Hopefully he have only mild symptoms.
Thanks Sr. , love your videos. You can realize how rich a man is when He shares
Never thought that the power supply could be designed thinking that the load would have more capacitors, makes sense! So, plugging the power supply from one equipment to another might not be a great idea even if the voltage and current are the same.
Very nice technical explanation of the circuit.
Could you do a video series on explaining the internal schematics of different analog IC's?
Like for example the mentioned TL431 (ti datasheet, Figure 24. Detailed Schematic), opamps, comparators etc.
Interesting that the charger’s left and right flap for AAAs move independently despite the manual forbidding you from mixing battery sizes. I think it is an oversight but maybe the creators wanted a little more versality (you can charge 2 AAs and 2 AAAs overnight at a safe current if you put the AAAs on the left side where the flap position is checked).
You can't charge 2 AAs and 2 AAAs, it uses the same current for all. It also terminates the charging for all batteries at the same moment. The AAs would not fully charge and the AAAs would overcharge.
@@DiodeGoneWild Yes, it senses the voltage of all batteries in series but I am not sure if you can overcharge a NiMH/NiCd cell, as they dissipate remaining energy as heat, so the AAAs would just keep toasting for a while while the AAs get (almost) topped up. So does not give great results but they are useful sometimes. Also, you would use the charging current optimised for AAAs so that they don’t experience overcurrent. Yes, it is a bad idea to combine cell types but if you know the inner workings of your charger, you can use this “option” in very specific circumstances, understanding what it actually does... But at that point such person would be probably skilled enough to modify their charger to accept mixed battery types at AAA current.
You can't overcharge NiMH/NiCd at a low charging current (0.1C, maybe 0.2C), but overcharging them at a higher current would damage them. 350mA for a typical AAA (about 900mAh) is almost a 0.4C charge rate.
@@DiodeGoneWild You are right, I forgot about that...
Polish transformer at 7:50 😁💪
This video is part of the reason why Elon Musk says going to college is not so necessary right now. There is just so much to learn of RUclips alone.
I love these videos. There's always so much to learn.
I have been away working on my channel....What did I miss!!!
Those Lidl Tronic NiMHs are some of the best I've used
Excellent video sir.
Hey Danie, you sound better. Keep these good videos
Nice videos, keep going on. I'm very interested to see how other build their SMPS. Low or high power I take everything xD
Nice video.
For the locked AAA rechargeable battery you need the put down positive contacts of the charger.
Interesting little Cyrillic Oscilloscope 😁
Great video. I love your accent!
Nice info... 👍
Flyback is especially great in drones.
It would be great if you could do a tutorial series of different SMPS topologies so that you would start with the simplest possible circuit and after explaining the core working principle would gradually add all of the other components like seen with this actual PSU. For noobs like me these sort of complete circuits look very confusing and you tend to go through the workings pretty fast. I haven't really found such tutorials so I think you'd be doing a big favor for many.
I can definitely recommend Haseeb Electronics for some great explanations on power supplies, as well as many other electronics too.
Nice clean waveforms and a nice safe transformer 😀
Yay, "dangerous USB phone chargers 11" coming up then :).
Anyway, nice analysis of the power supply... now I really want to see how safe the transformer is, because there are too many deices out there with dodgy electronics and poor electrical safety.
MOAR SMPS!
Polski transformator :-)
Great video, where did you get your isolation transformer and was it loads of money please ?....cheers.
I can’t wait for the electrocution death ☠️ devices in your next video!!!!
I love ❤️ when you tear things down and reverse 🔄 engineering with oscilloscope measurements too 🙃
Glad you didn’t destroy this one.
Yes, me too! I was worried about its transformer being unraveled. Nicely built PSU. It's not often you see that on cheap consumer electronics.
Please make a video showing us your technique of reverse engineering those schematics. Thank you!
The cat 😸 knows!
Great review, however, do you make this thick accent on purpose?
Hello, could you test the Chinese universal LCD chargers for 3.7V batteries?
wanted to ask is a power adapter safe if it has ntc thermistor and interference coil removed and bridged
How does a Capacitor between primary and secondary help?
is this a switch mode supply or is it called someting else? ix there a website that explains this kind of power supply?
Why there are so many different circuits for a SMPS? Can be 1 or 2 depending the cost savings and deliverable power?
I wish all chinese PSUs were as well made. Not a safety issue but i was a little surprised that the switching IC had up to 340v between adjacent 8 pin IC pins but I checked and it is enough of a gap.
Dismantle??
Can you explain the use and function of interference capacitor connected between primary and secondary of a transformer in an smps
He has covered its function in some other videos on SMPS designs. See: ruclips.net/video/cYN39g6qs-Q/видео.html
@@mysock351C
ruclips.net/video/jCuISR1brCY/видео.html
Is this and that are same
can you show oscilloscope wave form for the transistor in the optocoupler is it PWM feedback or the transistor acts as variable resistance in the feedback loop?
The optocoupler works in its linear region. The transistor acts as a "variable resistance", or more accurately, it can only pass a current proportional to the IR LED current. Optocouplers have a certain transfer ratio. If its 1 and the led gets lets say 5mA, the transistor will only be able to pass currents up to 5mA.
Zdravím Vás, děkuji za velmi poučná videa, které mi pomáhají pochopit principy činnosti spínaných zdrojů. Měl bych dotaz ke způsobu souběžného měření průběhů napětí na primární straně a sekundární straně pomocí osciloskopu. Jakým způsobem provádíte toto měření, máte nulový potenciál (zem osciloskopu) pouze na primární straně zdroje, nebo nulové potenciály primární a sekundární strany zdroje spojíte? Není potom problémem spojení obou nulových potenciálů (samozřejmě předpokládám použití izolačního transformátoru). Děkuji a přeji mnoho energie do dalších videí.
Měl to ve videu zapojené přes variak a pak přes izolační trafo :)
Sorry for my bad English. I live in a building that has never had problems with electricity, but my two laptops suddenly does not work properly, the cursor shakes when I connect the laptop to the charger, but not in all rooms, in some rooms it works fine, in some it shakes! I tried to turn the fuses from the right room to the wrong one, but again the cursor shakes in the same rooms as before! All other devices in the apartment work without problems, electricity works without problems, fuses do not blow out, cables do not stink, does anyone know what is the problem ???
ironically - the power supply uses standard screw and the 12V charger the safety type screws. should be other way round ? also the GS logo is obsolete for 2 decades...
a remark - 2 things i would find interesting in charger review: - can you test the fusible resistors in terms of fuse functionality - what current actually triggers them. and line current would be interesting to see how badly they are actually filtered
RUclips LIKE 544 - ODYSSEY LIKE 03 -- I Have supported the above video with 10 LBC forThe next 7 Days.
Thank you.
Can you please explain the need of isolation transformers when we need to prob the premary winding with that grounded scope?. What happens without isolation transformers.
This would be a nice video in Diodes style, but basically without isolation the scope internal 0V gets connected to ground and that can be live causing a short and your hard earned money goes down the drain.
Here's a much better description of what is happening with your scope and mains supply ruclips.net/video/xaELqAo4kkQ/видео.html Dave Jones puts this much better than I do !
@@andymouse Thank you.
Yes this EEVblog video is in my oscilloscope playlist.
Using an isolated transformers turns that mains earth reference power supply into a isolated power supply.
But i think he can disonnect the oscilloscope mains earth from IEC main connector instead of using an isolated transformer.
@@baghdadiabdellatif1581 Yes you can do that, I have worked in labs that do but it is generally frowned upon, I think its ok if its your scope and you understand and also that the plug is marked up clearly to indicate that there is no earth just in case someone else uses it !
@@andymouse Thank you.
I think in this case is better to probing a primary smps with disconnected power strip mains earth for the oscilloscope instead of an oscilloscope with disoldred mains earth.
MAKE VIDEO OF MEANWELL SMPS LRS SERIES
Or some people are just interested in both, the PSU and the ("dodgy") chargers :)
Flyback
So, the verdict? Not dodgy?
Probably Nice.
UWAGA: Nie przenosić transformatora za przewody!
Trochę drogi, w tme śpiewają sobie za niego 200 zł ;/
Trafo o 10x mniejszej mocy kosztuje 70 zł, więc jeśli nie potrzeba 200 VA to chyba taniej sczepić dupami dwa małe trafo z demontażu
I think we need more salt..
Made in 2010 ...
Ah, was it? I didn't notice that. That explains the well-made PSU.