Understanding Pulse Width Modulation - Part 1

Are you confused about Pulse Width Modulation (PWM)? Let's break it down to see what it is all about. Hope you enjoy the video and thanks for watching! There's also a part 2 to this video with real world examples. That video is located here • Pulse Width Modulation...

[@georgeheri895]

You are too good Terry, that was totally enjoyable. I'm sitting here going more ,more. Thanks for your time and effort.

[@stuzman52]

Why thank you very much George and glad to hear that you liked the video :) Hopefully, I'll be able to do a video on a car showing PWM and then we can tie all of this mumbo jumbo together LOL..Thanks again for dropping in and sharing a comment!

[@arthurfricchione6614]

Excellent video. Best I've ever had it explained to me. Also thanks to Eric O for sending us viewers in your direction. Will now be a steady follower of your videos thanks

[@stuzman52]

Arthur Fricchione thank you very much Arthur and hopefully in the next video we can show a practical example. 😀

[@j.jonahjameson6996]

Such a fantastic job of breaking down a complicated subject. Thank you

[@stuzman52]

Thank you very much J. Jonah!

[@octaviansorescu7427]

Greetings Mr. Stuzman! Today I bought a PWM module to test the Egr at Golf MK6 Tdi. I also bought two DC sources, one for the digital transducer that handles the position of the Egr valve. And one for the 12v motor that drives the Egr valve. You made me better understand how the PWM principle works. Thanks!

[@stuzman52]

Great to hear that you're getting into the understanding of PWM in purchasing a module. I was glad to help out with the video and hope your project works well.

[@duARTstudioChannel]

Thank you! Finally I understand how voltage change by changing the duty cycle and not the frequency! Good job.

[@stuzman52]

duART Studio Thank you for watching the video!

[@juergenscholl2843]

Very nice one, Terry. thank you for this easy to understand lesson.

[@stuzman52]

You're quite welcomed juergen and who says this electrical stuff is complicated :) Thanks for stopping in and leaving a comment!

[@normansmith7806]

Great job Terry ! Explained to where even I can understand !

[@stuzman52]

N Smith Hey Norman that's great! Thank you very much for sharing a comment!! 😊

[@1hlyGOD]

Thank you for ur time and expertise. ...I personally like when people explain things with a white board.. The biggest room in my house is the room for improvement. Every bit of information i can get is awesome. thank you again

[@stuzman52]

Drews Auto you are quite welcome Drew and it's always a pleasure. It's good to see you drop by and share a comment 😀

[@obediahgarcia2085]

Thanks for the awesome fundamental illustration and examples stutzman!

[@stuzman52]

Sorry Obediah for the delay as KZbin did not notify me. You're welcome!

[@billyr9840]

Nice ! Terry always love picking your brain ! your one smart cookie ! I am happy to here your going to do more vids like this ! Take Care !

[@stuzman52]

Billy R HaHa Billy, I wish I was smart. The more you learn the more you realize how much you don't know. I appreciate the comment and thank you for stopping in and sharing your thoughts. 😀😀

[@hammadijay5514]

great video thanks , i have a question please ? could you please help me with a diagram to build a circuit to generate pulse frequency 27 kHz, with a maximum pulse width of 39.0 -- 40.8 % of the cycle width.

[@armandonika]

Very valuable info thanks Terry, i really like these kind of videos!

[@stuzman52]

Glad you liked the video armando and I'll have to put more up like these! Thanks for dropping in and leaving your thoughts.

[@armandonika]

im really glad to hear that because i think since you are an engineer we all have something to learn from you, wish you all the bests!

[@paulfoldes3873]

would you do a video on bias voltage ox sensor please thanks Terry

[@codyjohnson1982]

Awesome explanation! I appreciate the video. Thank you.

[@stuzman52]

Sorry Cody for the delay as KZbin did not notify me. Thank you!

[@DylanRabier]

Hi sir. Excellent video on PWM basics. Didn't know you had your own channel. Cool!

[@stuzman52]

Yep Dylan, I've had it for a few years now and thanks for watching the video! :))

[@Badgertronix]

excellent explanation Terry. Thank you for the education.

[@stuzman52]

Thank you very much Jonathan! Hopefully folks will better understand how it works who didn't know.

[@DENicholsAutoBravado]

The duty cycle calculation surprised me a little but it made perfect sense. Since frequency remains the same, I had never considered counting the on and off together for the denominator as I figured it was a set value for a given circuit. It's a solid way to teach itnof course.

[@stuzman52]

DE Nichols David I am not sure why I did not get an email response from your comment and so I apologize for the delay in responding to you. Yes PWM is not that bad once you see how it all works. Thank you for watching the video and sharing a comment. 😀

[@zardow365]

Great videos sir, waiting for the next video. Thumbs up.

[@stuzman52]

Hashem Al-Husaini thank you very much and I'm glad you like the video and hope to put out more. Glad you dropped in to share some of your thoughts. 😀

[@haywardsautomotive6156]

Great explanation Terry. I love math but now I'm older I like selecting it and BAM done or SORTED :D Great video Terry!

[@stuzman52]

Hayward's Automotive Thank you very much Hayward and glad that you stopped by and left a comment! 😀

[@fire7765]

Thanks Terry great video as usual.

[@stuzman52]

gto 55 Thank you very much!

[@OneAuto]

Thats a great video Terry. Like you say we see PWM all the time in the automotive game and that was an easy to understand explanation. Well done sir!

[@stuzman52]

One Auto, thank you very much Rob for your comment and for watching the video. I hope to do a follow up video showing a practical example of how this is used. 😀👍

[@wyattoneable]

Wait, let me get my note book. Okay, go! And now were at the end. That equals...Outstanding!

[@stuzman52]

wyattoneable Thank you very much Wyatt and it wasn't that bad was it? Thanks for dropping in and sharing comment! 😀

[@bigsscore8378]

Excellent teacher, TOP MAN.

[@stuzman52]

Thank you very much!

[@ningarkumar389]

love u sir awesome class

[@octaviansorescu7427]

Excellent!

[@stuzman52]

Thank you very much!

[@123lightmovies]

very very good tutor you are

[@krishath7085]

Great tutorial Sir. Many thanks .

[@stuzman52]

Glad you liked it

[@spelunkerd]

Every time I turn around I find a PWM circuit, so there must be some reason for it to be so popular in automotive circuits. It seems to be a way of translating digital information into an analog output (or vice versa). I'm looking forward to your IAC description.

[@stuzman52]

spelunkerd hey Dave and hope you're doing well! You are correct that it is used everywhere in automotive circuits. The biggest advantage of why PWM iis used is because power dissipation is very low in the output stage which makes the circuit very efficient. I'll cover a little bit of this in the next video. Thanks for dropping in Dave to share a comment. 😀😀

[@ozzstars_cars]

Good explanation on PWM. I haven't seen that much algebra in 25 years! lol The future video on the IAC will be a good practical example on how it all comes together.....duty cycle, frequency and pulse width. Looking forward to it. Take care Terry

[@stuzman52]

Ozzstar Hey Glen and hope you're doing well! The next video will be an exhaustive look at calculus LOL. Yes I think a follow-up video on the vehicle will tie it all together. Thanks Glen for taking the time to watch the video and for sharing a comment! 😀

[@DENicholsAutoBravado]

stuzman I think I can still follow Calculus. ;)

[@stuzman52]

DE Nichols ha ha David! I'm sure I would have to pull the books out to remind myself of how it all works. 🤑

[@SouthMainAuto]

Great job Terry! Also is a great example of how the pulse pulse-width can change but the frequency stays the same very good jobs

[@stuzman52]

South Main Auto Repair Hey Eric, I'm glad you dropped in! You are exactly right that the frequency stays the same as the pulse width changes. I forgot to mention this in the video and only thought about it afterwards. And of course I forgot to mention about how PWM can have a different frequency based on the components for the load, Hopefully, I can do a follow up video on a vehicle and point out some of these things. Again thanks for dropping by and sharing your thoughts! 😀

[@TheDisgruntledMechanic]

+southmainauto Would a loadpro help with this?? ; )#

[@codyjohnson1982]

I was just watching your video on EGR testing Eric! Which led me here. You did some testing on an EGR that had 2 dedicated grounds so you said the EGR was controlled via pulse width modulation. Good stuff!

[@rrob4206]

thank you ......good job

[@stuzman52]

R Rob thank you very much and glad you like the video.

[@SchwanaCARDHUT]

Thank you very, very much ..!

[@stuzman52]

Schwana CARDHOUT You are welcome!

[@antegas]

thank you very much! mr. Stuzman . Like!

[@stuzman52]

Antegas Hindoyan you're quite welcome and glad to hear that you liked the video. 😀

[@antegas]

I learned a lot with your vid lesson mr. Stuzman. Thank you very much again.

[@stuzman52]

Always a pleasure to share in helping folks understanding how things work :)

[@bodgitandleggitgarage]

fantastic video mate great explanation I don't think many people realise exactly how much information you can get from a square wave especially when you put techniques and equations In to it

[@stuzman52]

bodgit and leggit garage you are correct Leon that there is a lot of information that can be obtained from simple equations. One example is calculating the inductance of a coil with nothing more than a voltmeter. Thanks for dropping in sharing a comment. 😀👍

[@bodgitandleggitgarage]

stuzman always love watching your videos mate i always learn something new

[@danielporojan4354]

When calculating Vout (and by that I'm thinking voltage across the lamp), shouldn't we consider Ton=1ms? That's because Vout should be calculated with respect to the time of the Duty Cycle when the signal is high. In the example above, that time is Toff. Or maybe, we keep these values, but we need to substract the final result, 8V, from Vin, which means Vout=Vin-8V, Vout=2V. I'm new to the concept of positive and negative sides switching and trying to make some sense out of it. Please clarify.

[@stuzman52]

Yes, you would be correct that with the example that I gave using a negative side switching, the voltage would be 2VDC although the time is on more at the bottom. At the time I did this video, I put the bottom pulse width on the top instead of using the top pulse width. When measuring with a DVOM, the meter doesn't know if the circuit is switched on the positive side or the negative side. As far as the voltage from the voltmeter's point of view, it's only sampling the voltage on the positive voltage in respect to the lower voltage. In other words, the positive voltage has the priority of how much voltage is going to be measured and it doesn't matter if the circuit is switched on the positive side or negative side. In the example that I gave, the top portion of the pulse is 1mS and the bottom portion of the pulse is 4mS . So, to calculate the voltage out, it doesn't matter whether it's switched positive or negative. Always use the pulse width on top divided by the total period * the Vin. So, that would me (1mS / 5mS) * 10V = 2VDC as you've already mentioned. One thing to keep in mind with the example that I showed which is the negative side being switched on is that the on time for the load is at the bottom where the current would actually flow for the circuit which is 80% of the period. Sorry XXL about the confusion. I redeemed myself in part 2 of this video series of where I explained this a little clearer with an example on a vehicle. You've got a good eye in catching that mistake! :))

[@danielporojan4354]

Thank you Tery for your quick reply. I can see clearly now ... :) I don't know what I like best, this in depth explanation or the wealth of knowledge you are sharing with us on your videos. I join the pwm enthusiasts on this page to congratulate you on your work!

[@stuzman52]

Thank you very much XXL and means a lot to me that you understand the concepts of PWM and thanks again for the comment! :)

[@EXOVCDS]

Great explanation of PWM! Formulas / equations make a lot more sense to me now... compared to when I was in school!

[@stuzman52]

I'm glad Thomas that I took a little bit of mystery out of PWM. I did have more on the board, but man, it was a little too much even for me so I had to delete it. Hopefully, I got the bulk of it across for a little better understanding of it. Thanks Thomas for dropping in and sharing a comment!

[@adhamraad8619]

Thank you

[@stuzman52]

Thank you for the comment and have a great day!

[@TheDisgruntledMechanic]

I was ok until you got to that algebra part with x's and V's and canceling out then I had l flashbacks to 8th grade! Thanks for the lesson Terry. Very well presented.

[@stuzman52]

The Disgruntled Mechanic Ah, it's not that bad Mike. As you said simple eighth grade stuff. Thank you very much for coming in and watching the video. 😀

[@thamerali9697]

Great

[@stuzman52]

Glad that you liked the video!

[@nickayivor8432]

INTELLECTUAL STUZMAN 👍 very helpful information video Take care and have a great day INTELLECTUAL STUZMAN From Nick Ayivor from London England UK 🇬🇧

[@stuzman52]

Thank you very much Nick and have a great day!

[@kyhomegarage3430]

Thank you so much for this class sir . This was very informative and easy to understand. Looking forward for next one. Its amazing how much we can learn each and every day from each other. KZbin is awesome. Thank you. Cheers

[@stuzman52]

Hi Ramon and hope you're doing well! This is all pretty easy stuff, but I kept seeing people talking about PWM, and realized that maybe folks out there didn't know what it meant. Hope the video will be helpful to folks and always glad to share. Thanks Ramon for dropping in and sharing your thoughts!

[@DENicholsAutoBravado]

ramon ruzic Terry definitely made youtube even better today.

[@stuzman52]

HaHa David! I don't know if I made KZbin better today, but I appreciate the comment! Hope all has been well with you and the family!

[@usmanhaider1060]

Hy Terry sir! Handsome you explain very well.....Tusi great o...

[@stuzman52]

Thank you very much USMAN!

[@DriveShaftDrew]

SO AS LONG AS YOU KNOW THE EQUATIONS YOUR ALL GOOD

[@stuzman52]

Ah, it's not that bad Drew...All pretty easy stuff here :) Thanks for dropping in!

[@DENicholsAutoBravado]

DriveShaft Drew lol

[@SteveRobReviews]

Well done Terry. Question - does the time it takes for the voltage to drop to zero or increase to the supplied voltage part of the calculated percentage value in the total duty cycle. Floating grounds have me puzzled too. LOL

[@stuzman52]

Hey Steve. With a square wave when it rises from 0 to supply voltage the time for this to happened is considered to be instantaneous which across time is 0. This holds true when it goes back from B+ to ground. In actual reality, there is a very, very small amount of time for it to go from one limit to the other, but even with a scope it would be difficult to measure. And this very small amount of time is not considered in the equation of calculating the PWM duty cycle. And what's confusing about the floating ground Steve; not much to it really :) Thanks for dropping in and leaving a post.

[@SteveRobReviews]

It's the floating grounds on gensets. It seems to me their set up in two versions some with floating grounds and some not . How does one tell the difference ?

[@stuzman52]

I'm not sure how I missed your post here Steve about the gensets. I only saw it when I was commenting to another viewer. I assume that you're talking about the neutral, right? The ground, (equipment ground is a totally different wire). If you're talking about why in some installations the neutral is floating and in others it's grounded, here's a link that hopefully explains the reason. If it doesn't make sense, just holler out again :) www.ecmweb.com/content/unraveling-confusion-over-generator-power-and-neutral-conductors

[@SteveRobReviews]

Thanks Terry

[@stuzman52]

Always glad to help Steve!

[@AbrarManzoor]

good

[@stuzman52]

Thank you!

[@AbrarManzoor]

@@stuzman52 rather i should thank you for this video

[@reynolflores2337]

Excelente video gracias por kompartir amigo preg de puede medir la amplitud del pulso y la frecuencia en inyectores y bobinas y en trasmisión automática del auto Kon fluke87v gracias información y ayuda de México

[@stuzman52]

Thank you very much! If I understand your question correctly, you're wanting to know if the Fluke 87V can measure the amplitude and frequency of PWM signals. According to Fluke's website, it says that it can measure PWM for motor driven signals. Although, I've never tried this feature, it something you can investigate. Good luck!

[@reynolflores2337]

Gracias por información comparado con el Fluke 88v cuál Cheka mejor el PWM o me sirve mejor p chekar pulsos gracias por ayuda

[@reynolflores2337]

Hola a todos feliz año nuevo lo.mejor p ti y tu familia sobre todas las cosas una pregunta kle es mejor un multímetro Fluke 88v o un FLUKE 87v trums

[@stuzman52]

@@reynolflores2337 Happy New Year to you and your family! For me, the 87V is a better multimeter although it costs more than the 88V which is more of an automotive meter. The 87V uses true RMS and is a little more accurate. For automotive use the 88V is fine, whereas the 87V is more for industrial use. Either one will work though. As for me, I have the 87V and have used it in both the industrial and automotive environments. Take care!

[@binbogamakine7803]

Anlamadım

[@thaeermsahib3133]

Sir you have wrong in your explanation at time 10:17 actually the time on equal to 1 ms not 4 ms so the numerator 1ms/4 ms+1ms the result is 0.2*100% its equal to 20% duty cycle finial result Regards I am Mr.Thair from IRAQ

[@stuzman52]

No Thair, the example shown is correct! :)) If you take a look at 10:17, you'll notice the pulse that you're referring to is 1mS wide, but you'll also notice that this pulse is during the OFF time. The example here is where the GROUND side is switched ON and that's where the 4mS on the numerator is coming from. In another example, I do show where the pulse is actually on which would be like you're referring to. In electronic circuits, the duty cycle depends on whether the B+ or the ground side is switched on. Thanks for watching the video Mr Thair, and I do appreciate your comment all the way from Iraq! :))

[@clems6989]

Yeah but you're measuring the voltage across the switch not across the load

[@stuzman52]

I'm sure that you're referring to where the load is switched on the negative side. I showed the voltmeter across the switch to emphasize that the circuit is energized when the switch is closed which would show 0V. Otherwise, across the load it would show 10V when energized. I felt showing the voltmeter across the switch would be a little less confusing to the viewer. Have a great day!

[@kickboxist]

Sounds like a NPC from RDR2

[@thamerali9697]

You are expected man

[@stuzman52]

Thank you!

[@thamerali9697]

I mean respected man

[@richardcamp7540]

Another great video. Think practical application would be much appreciated.

[@stuzman52]

I hope to do that in the next video Richard and thanks for dropping in :)