Hello there fellow EE! Some time ago in a music store I was with a friend and his girlfriend. She asked what RMS meant, and how it related to guitar amplifiers. I paused, and started running through my head how to explain it properly to a layman. She said "it's okay if you don't know". I really wish I had this video to help explain it at the time.
In 1988, right out of high school, I studied electronics engineering. I studied Ohm's Law, P=VI and RMS. But I never got around to why RMS is RMS. Now as a 50+ old geezer, I know. The animation at 4:05 is brilliant!!!
I have college and university degrees in electronics and electrical engineering, oh how I wish your tutorial and internet site existed then , I'm looking thru your sites , thank you
This is the most beautiful delivery I've ever experienced, the clarity of speech, the pauses to let it all sink in. This is a treasure. Thank you Sir. An enormous amount of effort has been put into this, resulting in the bringing about of perfection. A truly brilliant job.
Damn. That is one crystal-clear explanation of the RMS value. I know there is such a thing as RMS voltage in AC circuits but never could comprehend how it is derived. Hope I had RUclips in my college days..
Best explanations in the whole internet. Ive been days looking for explanations and there wasnt any video which make me understand. But this one is awesome. Thank you so much
This is not how I learned it but exactly how I understood it to be. Far too often do we expect others to teach us and make us understand. Yes, there are some teachers that are better than others, but that doesn’t diminish the responsibility we have to ourselves for our own understanding of a topic
I had a blurred idea about RMS. It started with measuring UPS and SMP power supplies. Understood that cheap multimeters cannot measure the correct voltage etc. You cleared it. Thank you!
It was decades ago, we went through the full derivation for RMS. About 15 years into my career I forgot how to derive it, but knew the sqrt of 2. Lol. This is a very nice review of the subject.
Great explanation after years of being an engineer we are getting to understand voltage and current 😂😊 I always thank God that there are scientists who think and research to help us understand such things .
Suprised To see a new way to derive The equation. initially I know a method to derive this equation using calculus but this method is more mind wobbling...
As an electrical engineer myself, this method explains how ac power formulas started, but the calculus wad explains the understanding of what the words Root Mean Square mean. You can't average and sine wave centered on zero, so square it, now its all positive, now average it (mean), now reverse the squaring(root). And voila RMS and you get the same answer Vpeak / root 2.
The peak voltage is usually used for capacitor. You must select capacitor voltage w/this voltage and no Vrms. In DC capacity the selected voltage must be function of the capacitor model. It is better 2 time more voltage than used dc voltage (specialy for tantalum).
Thank you for using the term Average Power. So many people who should know better think that the product of RMS voltage and RMS current is RMS power. That irritates.
The voltage changes in the US 60 times, in Europe 50 times. In Japan there are both networks, one 50Hz and one 60Hz, but only 100V RMS The voltage is 220V RMS in Russia, 230V RMS in continental Europe and 240V RMS in England. V peak is almost never used and V RMS is almost always used! V peak is only used when the AC voltage is rectified and the expected maximum DC voltage is asked. V RMS x SQR(2) = V peak V RMS x1,414 = V peak
This is by far the most clear explanation I have seen. Well done! Minor detail, at 8:55 it says that Vpeak is 325.3. I suppose this needs to be 352.3 (as it states a few seconds later correctly).
OMG, I've known about RMS for 45 years, but always thought household power was peak to peak. Even wired my own house from pole to multiple subpanels, how could I have missed that? Just one of the many new things I learned today....
RMS is the "square Root of the sum (Mean) of the Squares / 2" - By taking measurements of a sinewave evenly along both sides & peak, squaring each, add them together, then square root the sum which is the RMS voltage. The equation V=V/√2 is the simple method.
Nice. Thanks. Having exposure to this many times during my 40 plus year career in engineering and as a hobby as a young teenager I found that for RMS when I really got to the Root of this I found that Squares can be really Mean! 😮. Sorry. Humor. I really did like the presentation.
Phenomenal introduction. Future videos on phase discrimination and power factors would be extremely beneficial. For myself I have never been successful with teaching 746 watts = 1HP, but a 110v rms, 1 hp motor takes 10.2amps average.
Learned many years ago there are 4 looses in motors: stator, rotor, core & windage & friction. So the average AC t2 & 4 pole motors usually a 1 HP.Motor pulls 1,000 watts. Never trust HP rating on lying cheating communist china saws, drill presses etc. Way over rated.
Superb, and clear. Seems perhaps AI ( Artificial Intelligence ) may have assisted in the production of this video, as evidenced by the voice of the presenter.
What my professors with a phd could not explain was done here so brilliantly🫶🏻but here's another question, which parameter do the conventional Multimeters measure? If it's RMS (which really is), why? And if not, why?
Power can also be zero but not negative. Think about it intuitively. How could there be negative power? Either work is being performed (positive) or it isn't (zero). The voltage and current being either positive or negative simply refers to the direction the current is flowing. Regardless of direction work is still being performed.
So, the difference between either the V or I RMS and the effective peak voltage or current is basically the loss it happens during the power transmission!
So, if my RMS is 120V and the peak is 169.7V (as in 8:40) and I use a rectifier to convert it to DC, will I get somewhat 169.7V reading in a voltmeter at the end???
@@normstaley9799 "just an easy way to remember the numbers" That's good; whatever works! I have known this relation for decades but this video simplifies it considerably and removes trigonometric functions.
@@thomasmaughan4798 If you think all the algebraic steps this video goes through to get the answer is simpler than using the method I suggested then we should have a discussion on the meaning of the word SIMPLE
Sir l want to know what is differnes between RMS & PMPO and when the output power is given in PMPO IN amps how to calculet the RMS POWER OUT PUT OF THEAMP AWATING for teply pl pl
Doesn't Root-Mean-Square (RMS) imply SQUARING a time-varying waveform, then taking the AVERAGE (MEAN) value of that, and finally taking the SQUARE root of all that? My guess is that dividing the peak by sqrt(2) only gives the RMS value of a SINE wave, but other waveforms need the whole RMS sequence. Isn't this what "TRUE RMS" DMM's do for 'any' waveform? THANKS MUCH!!!! --dalE
Most of the cheaper multimeters give an approximate RMS value which is usually not that far off anyway. Multimeters are available that give a true rns value. It will probably tell you in the specs for your meter which one you have.
Power will not be +ve , it also varies from +ve to - ve like voltage and current , but understand a -ve or +ve will not matter in an appliance all it is only dissipation .
RMS Titanic didn't have the electric lines on when the crew members escaped before sinking. About 10 s escaped from the back part using a rope to a smaller ultra modern motor boat, designed today.
This is the stuff that drives you insane. If you are an engineer or even a hobbyist you do need to know this stuff. AC circuits can be difficult. Where was You Tube in 1992?
![Gunna - HIM ALL ALONG [Official Video]](http://i.ytimg.com/vi/w7Wf0h1Q8a4/mqdefault.jpg)
As an electrical engineer (myself retired), your explanation, with detail, is very well done ! Thumbs up. I've passed this along to others.
Hello there fellow EE! Some time ago in a music store I was with a friend and his girlfriend. She asked what RMS meant, and how it related to guitar amplifiers. I paused, and started running through my head how to explain it properly to a layman. She said "it's okay if you don't know". I really wish I had this video to help explain it at the time.
This is the single best presentation on Ohm's Law, DC and AC circuits that I've EVER seen! I've been doing electronics since 1972.
❤
In 1988, right out of high school, I studied electronics engineering. I studied Ohm's Law, P=VI and RMS. But I never got around to why RMS is RMS. Now as a 50+ old geezer, I know. The animation at 4:05 is brilliant!!!
Something a visual representation makes a concept much more clear and understandable.
I have college and university degrees in electronics and electrical engineering, oh how I wish your tutorial and internet site existed then , I'm looking thru your sites , thank you
This is the most beautiful delivery I've ever experienced, the clarity of speech, the pauses to let it all sink in. This is a treasure. Thank you Sir. An enormous amount of effort has been put into this, resulting in the bringing about of perfection. A truly brilliant job.
Damn. That is one crystal-clear explanation of the RMS value. I know there is such a thing as RMS voltage in AC circuits but never could comprehend how it is derived. Hope I had RUclips in my college days..
Best explanations in the whole internet. Ive been days looking for explanations and there wasnt any video which make me understand. But this one is awesome. Thank you so much
This is not how I learned it but exactly how I understood it to be. Far too often do we expect others to teach us and make us understand. Yes, there are some teachers that are better than others, but that doesn’t diminish the responsibility we have to ourselves for our own understanding of a topic
I had a blurred idea about RMS. It started with measuring UPS and SMP power supplies. Understood that cheap multimeters cannot measure the correct voltage etc. You cleared it. Thank you!
Best video as an electrical engineer i have ever seen explaining this...
It was decades ago, we went through the full derivation for RMS. About 15 years into my career I forgot how to derive it, but knew the sqrt of 2. Lol. This is a very nice review of the subject.
Great explanation after years of being an engineer we are getting to understand voltage and current 😂😊
I always thank God that there are scientists who think and research to help us understand such things .
Good job. You managed to explain a not simple concept using concise and effective approach.
If I’d have known this analogy during my study it would’ve saved lots of time and could pass the class with better grade
this is pure gold. one of the best videos ive seen. thank you very much
Wow, thank you!
I have known about the RMS formula for at least 30 years. It's the first time that I know from where this equation comes.
Why youtube and guys like you didn’t exist in 1992? DZIĘKUJĘ 🎉❤😊
Beautifully explained, thank you!
Thanks machn.. happy to see sri lankan channel in this topic
Suprised To see a new way to derive The equation. initially I know a method to derive this equation using calculus but this method is more mind wobbling...
As an electrical engineer myself, this method explains how ac power formulas started, but the calculus wad explains the understanding of what the words Root Mean Square mean. You can't average and sine wave centered on zero, so square it, now its all positive, now average it (mean), now reverse the squaring(root). And voila RMS and you get the same answer Vpeak / root 2.
The peak voltage is usually used for capacitor. You must select capacitor voltage w/this voltage and no Vrms. In DC capacity the selected voltage must be function of the capacitor model. It is better 2 time more voltage than used dc voltage (specialy for tantalum).
as a retired ECE this should be the way we teach this to kids.
Thank you for using the term Average Power. So many people who should know better think that the product of RMS voltage and RMS current is RMS power. That irritates.
Very nice topic for basic Electrical engineering
The voltage changes in the US 60 times, in Europe 50 times.
In Japan there are both networks, one 50Hz and one 60Hz, but only 100V RMS
The voltage is 220V RMS in Russia, 230V RMS in continental Europe and 240V RMS in England.
V peak is almost never used and V RMS is almost always used!
V peak is only used when the AC voltage is rectified and the expected maximum DC voltage is asked.
V RMS x SQR(2) = V peak
V RMS x1,414 = V peak
Fascinating! Wish I had learnt it like this in the early 80s!
If you were my electrical engineering professor, I surely will have the best grades❤
Unbelievable
Very interesting 👍
Thanks
The best video with the best and simplest explanation I have ever seen
Very well explained. Thank you very much for sharing this video 👍
This is by far the most clear explanation I have seen. Well done!
Minor detail, at 8:55 it says that Vpeak is 325.3. I suppose this needs to be 352.3 (as it states a few seconds later correctly).
OMG, I've known about RMS for 45 years, but always thought household power was peak to peak. Even wired my own house from pole to multiple subpanels, how could I have missed that? Just one of the many new things I learned today....
A negative voltage multiplied by a negative current gives always a positive power. Power then cannot be negative.
Thank you very much. Im electric engineer but never understand these . Thank you
Best video on this topic uptill now 👍👍👍
RMS is the "square Root of the sum (Mean) of the Squares / 2" - By taking measurements of a sinewave evenly along both sides & peak, squaring each, add them together, then square root the sum which is the RMS voltage. The equation V=V/√2 is the simple method.
And that's why we use it - it's simple. It's only necessary to use a more sophisticated approach for non-sinusoidal waveforms, would you agree?
NOW I understand. Thank you very much. 👍
Excellent Professor
Nice. Thanks. Having exposure to this many times during my 40 plus year career in engineering and as a hobby as a young teenager I found that for RMS when I really got to the Root of this I found that Squares can be really Mean!
😮. Sorry. Humor. I really did like the presentation.
Thank you I use in study in 12th-Sci
it was amazing.
Thank you
Phenomenal introduction. Future videos on phase discrimination and power factors would be extremely beneficial. For myself I have never been successful with teaching 746 watts = 1HP, but a 110v rms, 1 hp motor takes 10.2amps average.
Learned many years ago there are 4 looses in motors: stator, rotor, core & windage & friction. So the average AC t2 & 4 pole motors usually a 1 HP.Motor pulls 1,000 watts. Never trust HP rating on lying cheating communist china saws, drill presses etc. Way over rated.
The RMS value is .707 x peak value of a pure sine wave
Yes, 0.707 being an approximation of 1/(square root of 2).
Brilliant explanation using the animation. Liked it!
Wow! 🤩 you smashed it👏🏻👏🏻👏🏻👏🏻
Very good videos. I liked the voice, too. I liked the water analogies. I’m going to look at your other videos. Thanks
Awesome, thank you!
thank you so much for your explanation, is wonderfull
Very good, I wish you could cover more topics
thank you, very good explaination.
Superb Explanation
Thank you 🙂
Best job think you for this
Great presentation, thank you.
Superb, and clear. Seems perhaps AI ( Artificial Intelligence ) may have assisted in the production of this video, as evidenced by the voice of the presenter.
This is gold
Next video ÷ how to transformer less(Capacitor) power supplies work. It Actually convert the voltage? And how about efficiency.
Excellent explanation
Super explaining. ..
Wonderful presentation and animation! Keep it up
However, here
II do not see any mean square .
Do it with the mean square. Using statistics formula.
Very clear man 👍
Excellent..!
Thank You. 👍🏻
What my professors with a phd could not explain was done here so brilliantly🫶🏻but here's another question, which parameter do the conventional Multimeters measure? If it's RMS (which really is), why? And if not, why?
Very useful
The current changes direction 100 times a second (120 times in North America). It goes through 50 (60) complete cycles per second.
Good job
Yeah, so far, so good. But how does one come up with RMS voltage and current?
Thank you for information khalid du Maroc Casablanca
Awesome
New subscriber always watching your videos very interesting❤
Nice Explanation I have a one question that why power is only in positive
Power can also be zero but not negative. Think about it intuitively. How could there be negative power? Either work is being performed (positive) or it isn't (zero). The voltage and current being either positive or negative simply refers to the direction the current is flowing. Regardless of direction work is still being performed.
man thank you so much
THE GOAAAATTTT
So, the difference between either the V or I RMS and the effective peak voltage or current is basically the loss it happens during the power transmission!
This is so interesting
So, if my RMS is 120V and the peak is 169.7V (as in 8:40) and I use a rectifier to convert it to DC, will I get somewhat 169.7V reading in a voltmeter at the end???
simply put - to find Vrms multiply peak voltage by the sin of 45 degrees, and divide Vrms by sin 45 to get peak Voltage
It works but has nothing to do with sine per se; just that the sine of 45 degrees (in a 360 degree circle) just happens to be the square root of 2.
@@thomasmaughan4798 I didn't mean to imply that it did, just an easy way to remember the numbers
@@thomasmaughan4798 also the presence or absence of a "360 degree circle" has no bearing on the sin of any angle
@@normstaley9799 "just an easy way to remember the numbers"
That's good; whatever works! I have known this relation for decades but this video simplifies it considerably and removes trigonometric functions.
@@thomasmaughan4798 If you think all the algebraic steps this video goes through to get the answer is simpler than using the method I suggested then we should have a discussion on the meaning of the word SIMPLE
In other words, RMS value is the DC equivalent voltage in order for the circuit to consume the same power if connected to a DC source. Am I correct?
Great video. love the tiktok voice
We use 60 Hz in the USA and the direction of the current changes 120 times a second.
thanks
what can i say, apart from 'Shocking' 🙂
I think that the Average value is actually .637 of the peak. Avg= P * .637. So 169v*.637= 108.12vac.
👍👍
Next - power calculation in three phase circuits
Muito bom
Is this concept of average AC power applies to both 1 and 3 phases systèmes ?
Sir
l want to know what is differnes between
RMS & PMPO and when the output power is given in PMPO IN amps how to calculet the RMS POWER OUT PUT OF THEAMP
AWATING for teply pl pl
What service does the voice over. Everyone is using it.
I'd love to know as well. Unfortunately it's used for a lot of garbage, and this video is very much the opposite.
Thanks, never heard of this.
👍
Doesn't Root-Mean-Square (RMS) imply SQUARING a time-varying waveform, then taking the AVERAGE (MEAN) value of that, and finally taking the SQUARE root of all that?
My guess is that dividing the peak by sqrt(2) only gives the RMS value of a SINE wave, but other waveforms need the whole RMS sequence. Isn't this what "TRUE RMS" DMM's do for 'any' waveform?
THANKS MUCH!!!!
--dalE
My multimeter measured household peek to be 120v. Are multimeters RMS?
Most of the cheaper multimeters give an approximate RMS value which is usually not that far off anyway. Multimeters are available that give a true rns value. It will probably tell you in the specs for your meter which one you have.
50 Hz in europe, 60 Hz in the US.
But in the Europe we usually have 400 V (RMS). Peak value is approximately 566 V.
400 V is the voltage *between phases* in a 3-phase system: 230 V * √3 = around 400 V.
230 V is the RMS voltage between any phase and ground.
👍💙💙
Shanilka Ariyarathne
you said 325v on the last slide but the graph says 352.3v. Typo
Power will not be +ve , it also varies from +ve to - ve like voltage and current , but understand a -ve or +ve will not matter in an appliance all it is only dissipation .
RMS Titanic didn't have the electric lines on when the crew members escaped before sinking. About 10 s escaped from the back part using a rope to a smaller ultra modern motor boat, designed today.
This is the stuff that drives you insane. If you are an engineer or even a hobbyist you do need to know this stuff. AC circuits can be difficult. Where was You Tube in 1992?
Странно. Если сравнивать площадь полуволны и прямоугольника такой же ширины, там не корень из 2, а Пи делить на два.