All You Need To Know About PFC To Fix Stuff : Power Factor Correction For Beginners

PFC is used in a lot of Switch Mode Power Supplies and other applications. But what is PFC, What does it do and how does it work? And even more inportant what goes wrong? Learn All You Need To Know About PFC To Fix Stuff Here!
Find the full All You Need To Know Series here
• The ALL YOU NEED TO KN...
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Thank you
Richard

[@adambradley3284]

31:53 " Probly needa new paira trousers ok" love it! Great video as always.

[@pierretessier1682]

Wonderful, you made a real good job for explaining de PFC in simple words, no maths. Thank a lot for your works!

[@christopherbullard835]

Thanks Richard! You are a very wise young man and a great teacher! Thanks so much for all you do for us.

[@garypoplin4599]

33:30 - Thanks for adding that in (even if it were just an afterthought!) Before, it was difficult for me to understand how a single power supply could be used on such a wide range of input voltages. Until now, it had been somewhat of a mystery to me. I learn something from you every time I see one of your videos (some times it takes my watching them more than once to get all the nuggets out of them)!

[@Patecabraltica]

Hi, Richard. Thanks for this, it explains nicely how PFC works, which I didn't quite understood until now. And the last 7 minutes or so are GOLD, because you MIGHT make the mistake of trying to measure the main cap voltage in the bridge rectifier, being this such a common practice. I made that mistake once with a minicomponent power supply, and got a shock, fortunately only an annoying, not a deadly one. Made a video of it in my channel as a warning, but I'll better update that and explain that we should "look out for it" when we got an active PFC in our board. 👌

[@SoyapiChirwa]

Excellent explanation on pfc Zambia keep it up

[@Mcfreddo]

I did enjoy it, thank you! Your lessons are fantastic.

[@chrishartley1210]

I think you have it backwards about the way power companies apply charges. Standard meters measure watts. The new smart meters are capable of measuring both VA and watts. In a purely inductive or purely capacitative circuit the VA measurement will be bigger (sometimes by many times) than watts measured. The reason why power companies want everyone to have smart meters is so that they can switch the charging method. In some cases the cost can change from a few pennies or cents to several pounds/euros/dollars. At the moment, power companies make up for the difference with a portion of the daily standing charge. Those with PFC devices are effectively being charged twice. If they change the way power is measured the price per VA will be less than the price per watt but will more accurately reflect the energy consumed. That means the daily standing charge should drop but it is unlikely that it will.

[@deangriffiths8107]

Exactly why I never had and never will have a smart meter fitted.

[@LearnElectronicsRepair]

That was meant to be a bit tongue in cheek 😅

[@enchanter976]

Brilliant lesson, I always wanted to learn how these modern power supplies work, Thank you Richard 😊

[@stevewebb1941]

Very nice video we should all start with this video doing electronics

[@rahulmechatronics]

Thank you Richard... very nicely explained the concept of PFC 👍👍👍...... greetings from India

[@k3ggaming926]

This was same explanation as haseeb and you guys are doing a great video for us who is willing to learn electronics by just watching youtube and apply it on actual board. Thank you guys❤❤❤❤

[@LearnElectronicsRepair]

That's even more interesting as I haven't seen Haseeb video on this topic

[@surgingcircuits6955]

This is a very important/useful video, answers many questions, and is really appreciated. TY!

[@jerrodrollins1509]

I really appreciate how you explain things in a way that us "dummies" can understand. Caveman talk

[@LearnElectronicsRepair]

Thank you 🙂

[@warwickbunn1250]

He's got a tough job as some of us are particularly... um .... challenged (me) 😆🤣🤣 So I may have to watch this again, and again. But I love all these videos. 👌 Thanks Richard.

[@LearnElectronicsRepair]

@@warwickbunn1250 If it doesn't make sense let me know what parts are confusing. I do hope that isn't all parts but I do admit this is a hard concept to get your head around

[@wtfucrazy]

Thanks! great work

[@Lightrunner.]

I love the expression GND🥰.... VSS or VEE are weird names 🤖.

[@thebloody_blue]

I'm a big fan of you. 👌

[@melvilib]

Thanks Richard, I knew what and why, but now know how 👍

[@samithetechsavvy6485]

thank you very much

[@ser_olmy]

Most power companies charge you extra for the maximum current load, and some will charge according to the overall Power Factor of an entire building. There's a good reason for that, which also is a good argument for performing Power Factor Correction. As shown by the first drawing, a component with a PF < 1 will not be able to make full use of the maximum AC voltage. This means that in order to generate a desired amount of power, more peak current has to be drawn (because the maximum current isn't drawn when the voltage is at its highest, and P is still U x I). A device doing this is not actually wasting any power, just drawing more current at a lower voltage to achieve the same result. However, as the diameter of power lines and mains cabling is directly related to current, not voltage, power companies have to install bigger/more lines to supply power to equipment and sites with a lower PFC, even though the overall power drawn might be the same. Since lines = copper + installation, and copper + installation = money, power companies would much prefer it if your PFC is as close to 1 as physically possible. Oh, and this obviously works on a local scale too: You might think that the "I" amp circuit in your house in a country with a mains voltage of "U" should handle a load of I x U Watts, but if the combined PF of the devices you're powering is less than 1, the breaker (which only deals with current) will trip well before you get to the theoretical maximum.

[@LearnElectronicsRepair]

Thank you so much for your input here, this is a difficult concept to understand or try to explain without using maths that a lot of people would not understand anyway.

[@Dutch_off_grid_homesteading]

Heya, very nice explanation of the pfc love it and untherstand it.

[@lawrencehalpin6611]

Thank you. Kind regards.

[@RuneInternational]

should it not be just 0.95 or 95%

[@LearnElectronicsRepair]

Sorry, I mixed that up

[@jameslineham9761]

Great job, Thanks!

[@dougiee6589]

I think now how the power cleaning devices I bought off temu actually clean dirty power and saves your power bill. Thank you

[@markweiss5152]

Power Factor Correction. thank you. to get a good understanding of how much deference it makes. The deference in speeds of most ceiling fans is all due to Power Factor Correction. Low speed = no Power Factor Correction. medium speed = some Power Factor Correction. high speed = full Power Factor Correction.

[@Monaco-BuilditFixitDriveitEver]

Interesting.

[@phillipchen7749]

nice tutorial on pfc operation

[@viniciusvbf22]

Hello, Richard! Thank you so much for this lesson. It know it may be way too simple, but, if you can find the time, could you please make a video explaining about current sensor resistors? I'm always lost when thinking about how can a 1 ohm resistor "sense" 10 amps of current (since it will have about 10 watts going through it, I think). Again, thank you for all your videos. I wish I can repay you and so many other youtubers that teached me so much someday or, at the very least, thank you in person and bring you some gifts. Cheers!

[@LearnElectronicsRepair]

Sure, I'll make a video about this topic

[@jeremylaidman6525]

It's because the voltage across the resistor increases as the current increases, by Ohm's law. A 1 ohm resistor with 10 amps running through will have 10 volts across it. So the PWM/PFC chip is measuring volts, to know what the current must be.

[@nasosst3092]

32:00. we can always wash the trousers and get ready for the next BANG dear Rick

[@LearnElectronicsRepair]

pmsl

[@nasosst3092]

Plus one question: there probably is a voltage feeding circuit after the initial start to serve the pfc chip vcc during normal operation. Some info about this plus a simple schematic would be interesting

[@Masinger17]

Blessings !!! Thanks for that important and interesting information !!! I have a power supply "Corsair" TX850M (of course 850 W.) and I changed the main capacitor ( 560 uF , 400 V ) because it was blown. I bought and put a 860 uF, 400 V in its place thinking that it will fix the problem but it didn´t and as soon as I connected the PS, the new capacitor began to make a shshshshsh sound and smell in the specific way. So the capacitor was not the problem but the victim of a malfunction which I suspect is located in the PFC. Something is causing to raise the voltage above the 400 V which the capacitor can handel. Can you give me any hints to solve this problem ? I´m not a professional of electronics, I´m just trying to fix my power supply; but I´m also learning a lot about these apliances and I find them fascinating !!! Blessings again !!!

[@tonysheerness2427]

Very educational, learnt something useful. How are the tourists in your part of Spain as in Magaluf the beaches a deserted?

[@LearnElectronicsRepair]

Quite busy. Though May into June is our low season, July/August and the winter months are much busier

[@barryjensen296]

I think you have it wrong. VA is always >= Watts. Electric companies generally charge for Watts. But can charge for "demand", maximum VA. This is common in industry.

[@mohbit3336]

Hello, friend I've got a expensive power supply if you can help it outputs 12v 4.5amp,24v 6amp with active pfc the pfc start at 370v when I try to drive 1.5amp from the 24v rail it drops to 300v at 12v rail it drops to 350v at full load (I disconnected the 24v rail) what do you think is't the 24v or pfc ?

[@steve-h7z]

10:40 wonder what the power factor is on this passive Pfc? is it close to 0.8?

[@jeremylaidman6525]

On active PFC with power source removed, can the residual voltage across the big cap be measured across the diode, given that one side is at cap potential and the other side is at bridge rectifier potential, which is zero?

[@مصطفىالربيعي-ت8غ]

Amazing lesson as usual, but I didn't understand how this circuit got the current wave to be close to voltage wave, I understood it is trying to keep the capacitor 390v all the time but in terms of wave didn't get it, can you please explain a little bit to make it more understandable. Many thanks for your efforts

[@LearnElectronicsRepair]

It didn't exactly, I used a bit of poetic license to get the principle over. 😇 The switching mosfet will cause very rapid voltage changes in the waveform. But the filters on the input (capacitors, inductors) remove the high frequency switching noise and you then end up with a waveform like the one I showed

[@analoghardwaretops3976]

In this pfc controller topology there is only a small (1-2 )uF cap...and no large filter cap.. So the rectified dc is a " ripple" dc with ripple freq. of 100/120 Hz. this ripple voltage goes down to almost zero Volts @ zero crossing... Now assuming your load (design. req.) is decided as 5 amps (dc) ...internal to the pfc chip this 5A ( target ref.) is first converted to a (100/120Hz)ripple DC..... equivalent of 5A . For conversion to this , it in turn uses the 100/120Hz " Voltage ripple" as its reference....and is tracked in an internal feedback loop. Thereby now the input current wave shape must & will follow/ track input voltage wave shape.. So the distortion/ perturbations in the input voltage waveform are copied into the current ref. & hence onto the output.. Hence it is of utmost importance that the ripple voltage waveform be the exact replica of the input voltage... now, since the ripple current is always tracking the ripple voltage , & is in phase , we are able to achieve an almost unity power factor . Hope you can follow/ understand this long drawn explanation of mine .😅

[@aliemlek]

👌👌👍👍

[@alfordmyers7786]

What happened to ELI the ICEman?

[@davidhollfelder9940]

Passive PFC is “passé”

[@unintendedperson]

can we disable pfc when the pfc pwm and smps pwm is single chip?

[@LearnElectronicsRepair]

Probably not as the PFC controller is monitoring the boost voltage. But no doubt it depends on the chip type

[@Lightrunner.]

Why would you do this ?

[@LearnElectronicsRepair]

@@Lightrunner. It's a useful repair technique, if you have for exampe a short circuit PFC mosfet on a 'combined' PFC+ PSU+Load type PCB, for example you could find in a TV, you may want to disable the PFC by removing the shorted Mosfet and see if the rest of the board will power up with say (non-boosted) 320V in the bulk smooting capacitors or if you have other faults too.

[@Lightrunner.]

@@LearnElectronicsRepair ohhh, sorry. My question had a different background. I hadn't thought about repairing it😪.

[@leetucker9938]

what is hot ground ?

[@SilliestSmurfEver]

Lava

[@mikebond6328]

Negative rail. Not earth ground.

[@deangriffiths8107]

Lee go and watch some of Richards earlier videos on switch mode power supplies.

[@LearnElectronicsRepair]

Oh, that is such a good and important question I must go make a video specifically on that. Next week 😁

[@LearnElectronicsRepair]

@@SilliestSmurfEver hehehe yeah