Why Does An ATX Power Supply Have Two Main Smoothing Capacitors? How ATX PSU Works Tutorial

Have you ever wondered why an ATX Power Supply has two main smoothing capacitors after the bridge rectifier? Did you ever think they could just fit one larger capacitor instead? Well now you can find out how this circuit works, no maths, no waffle, no fluff just the facts you need to know to understand and fix this stuff!

I work in collaboration with:
The Electronics Channel (live streams with Carlos and Detlef)

Gran Canaria Uncovered

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TEST METERS
ANENG AN8009 MULITIMETER
KAIWEETS HT118E MULTIMETER
VC480C+ MILLIOHM METER
MESR-100 ESR METER
XC6013L CAPACITOR METER

TM-902C TEMPERATURE METER
LCR-T4 COMPONENT ANALYZER
FNB58 USB ANALYZER
PCI POST ANALYZER
TL460S PLUS PCI_E ANALYZER
TOOLTOP ET120MC2 SCOPE
FNIRSI 1014D SCOPE
NPS3010W 30V 10A PSU
T12 STATION WITH M8 9501 HANDLE
M8 9501 HANDLE
YIHUA 982 Soldering Station C210/C245
FNIRSI HS-02 PORTABLE SOLDERING C210/C245
QUICK 861DW
PROS'KIT SS-331H

INFIRAY P2 PRO IR CAMERA + MACRO LENS
TOOLTOP ET13S THERMAL CAMERA METER
ET13S MACRO LENS
OPTICAL MICROSCOPE
TOMLOV TM4K AF FLEX
TL866 II+ PROGRAMMER
CH341 PROGRAMMER
NC-559-ASM FLUX

DESOLDER BRAID (I use size 8045)
HX-T100 SOLDER (0.6MM)
ESD-11 TWEEZERS

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Thank you
Richard

[ColinMcCormack]

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!

[seabeepirate]

I didn’t realize the video was 42 minutes long until it was over. Well done.

[spoonmanxx]

I'm just 7 minutes into the video and this is the most I have learned about power supplies.

[tonysheerness]

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.

[bazrazin]

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.

[jamesgrant]

I have learnt more in 45mins with you than any other presenter

[alanpaulsy]

the effort put here is so impressive.
Universities must include this to better their lecture

[messageobliquespe]

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 👍

[_ndot]

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.

[leearft]

This was an excellent presentation on how this type of PSU operates, the bell analogy for resonance is the best I've seen.

[louf]

The thoroughness and pace is very appreciated.

[paolomonai]

Dear. Rich, bell analogy to explain LLC topology is simply...fantastic! Never thought that way...regards from Italy.

[davet]

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 .

[is_what_it_is]

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.

[aalkounis]

You are the best teacher I never had.
I learned more about circuits and electronics in 42min. than 4 years in the University.

[richardf]

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. :)

[abhb]

practically explained perfectly ... the bell was the obsolute example for a resonator 😊😊👍👍👌👌

[jasejj]

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!

[miket]

Of several youtube videos on this subject, your video was by far the best explanation. Thank you!

[kennytinker]

Very informative, feel like i am back in school, new suber after watching this. Ty for your effort and time.