Intro to Pulse Width Modulation

[@StealthParrot]

Fantastic explanation, thank you!!!

[@andymouse]

Fascinating !

[@kesor6]

Excellent explanation! I was expecting to see an example of removing the triangle wave, similar to how it was added in the first place, using an opamp. Maybe next time?

[@ElectronicswithProfessorFiore]

Not sure what you're saying. The triangle wave is used for the encoding process.

[@breedj1]

Excellent video. Side note: in reality one should not use op-amps like a TL081 as comparators, but real comparators. Op-amps are not designed for use without a feedback network. Their inputs will saturate when the differece between them is more than a few mV.

[@ElectronicswithProfessorFiore]

Yes, this is true and I talk about such things in my op amps textbook (free download, link in video description). The main reasons to use proper comparators are that they tend to be faster and it is easier to set up their output levels. The reason I use op amps here is because virtually every simulator will have a decent general purpose op amp in its library if a student wants to do their own sim, and it is easy for students to hook up such a circuit in their own lab with parts on hand. I prefer not to use specialized parts for instructional videos when general purpose parts will be sufficient to show the concepts.

[@stephens1393]

Cool video. If it's really an intro for teaching, I might - explain more what PWM is used for and _why_ it is used (for power purposes, it is inefficient/difficult to produce analog signals, but switches are cheap and efficient; for informational purposes, analog signals are susceptible to noise, whereas PWM is less). I feel there are really two separate purposes-- information and power. They may hear about servo (control/information) PWM and be a bit confused how it relates to power PWM (the control aspect is also typically generated in a very different way, also, i.e. a microcontroller). You seem to focus primarily on the power aspect here, but you might want to mention the usage relating to control/information in case they are thinking about servos they've used. - discard everything about harmonics and focus on average energy or power in the signal. This is more understandable from a basic math perspective that beginners have, i.e. averaging rectangles is easy (otherwise you're just teaching them to throw around buzzwords like "harmonics" that they probably don't fully understand). It's a nice tutorial on the basics of PWM. Reminders of the different types is interesting.

[@ElectronicswithProfessorFiore]

Yes, it is an intro, and it is designed to support the discussion in my free textbook which goes into much greater depth (links to my textbooks are in the video description).

[@jamesbelcher5318]

In this case why would you modulate the signal then demodulate it? I understand it's for purposes of demonstration, but would have like to see how it would work with a class D amp as you suggested.

[@ElectronicswithProfessorFiore]

The pulse train is the signal you'd run into the class D output stage. More details in the chapter on class D amplifiers in my free Semiconductor Devices textbook (link in video description).

[@gothesouthway]

Oh no, not Utica NY. I once walked from Utica to Madison. Not fun.

[@ElectronicswithProfessorFiore]

That's quite a hike. Must've taken several hours.

[@gothesouthway]

@@ElectronicswithProfessorFiore it did, I left about 5PM and didn't get home until 2 AM. BTW great video.

[@ElectronicswithProfessorFiore]

@@gothesouthway So, not only did it take you nine hours, but you also did most of it in the dark? Ouch. You're lucky you didn't get side swiped and killed.

[@gothesouthway]

@@ElectronicswithProfessorFiore I was tired from work, and do you realize how dark it gets out there? I was more terrified a wolf or something was going to jump out from the tree line. I got a job closer to home after that. (home being Phoenix, Az... with a bus service)