Electrical Engineering: Ch 10 Alternating Voltages & Phasors (7 of 82) Adding Sinusoidal Functions

In this video I will explain how to find the phase angle difference between two phasors and how to add to phasors together on a phasor diagram.

Next video in this series can be seen at:

[smcm]

Thank you so much for this video series. I am currently in a ciruits class and the instructor does not do a satisfactory job of lecturing. Your videos are extremely clear, concise, and well paced.

Again, thank you for everything you've done.

[righteousness]

i've seen your other videos, excellent teaching. I like how alot of your videos are about 5 minutes, yet very comprehensive at the same time.

[ahsanhabib]

Thank you sir. You can make things so easy to your students. Love from Bangladesh.

[aaron]

Hi, your math was indeed correct, but you made a small oversight which is causing some students to be confused. You should use the identity -cos(wt) = cos(wt+180) = cos (wt-180), which is the equivalent to what you wrote, but matches your work better for v1(t), since we are adding/subtracting 180 when the amplitude is positive, not negative. It is similar to why we are subtracting 90 for v2(t) when the amplitude is positive.

[stefanleo]

Thanks for teaching the theories.... I finally solved my task!

[JoshuaWGbuah]

Thank so much, I have been struggling to understand this topic.
Sure you are a legend.

[EigenA]

I’ve never seen axis set up like this. I understand a -90 sin shift results in a cos and therefore there is nothing incorrect about the setup but is the purpose of this just have a graphical representation of phasors?

[GERBINO]

michael you said it doesnt matter if you add or subtract 180 to change negative to positive but if you say 60 +180 it gives you 240 and if you subtract 180 from 60 you get -120 it produces different answers

[rrekeitebetse]

I think there is something wrong, if we want to change from sin to cos with keeping positive sign, just add 90, but if we subtract 90 we will get negative cos, isn't it? I know sinx=(cosx-90) and cosx=(sinx+90) and here we are intrested in finding cos in which its supposed to be + 90. revisit it and look at it precisely, they are not the same and they will not give the same answer. I appreciate ur work sir

[nareshchandraverma]

Q. Two identical spherical balls of density D are suspended on vertical threads at a distance r from each other in vaccum. The balls are given equal charges and immersed in a liquid of density d and dielectric constant K. If threads are not deflected from the vertical in vaccum as well as in dielectric liquid. Then

[azizmizrobov]

Changing V2 from sine to cosine, can we say 3sin(wt-20+90)=3cos(wt+70), as we know sin(wt+90)=cos(wt)

[SS-pnss]

Very very well explained, exactly what I was looking for: thank you.

[brindhagopalan]

Really good explanation, please do keep making more videos so we can understand

[munnamonk]

Wish I would be taught in my class likewise 😅. Thanks Sir ❤️🙏

[joshuaflores]

You are the best! Do you have a website similar to the Youtube tutor, Math and Science?

[ahmedal-ebrashy]

Sir is there a reason that the positive sine is draw downwards axis. I find it counterintuiive that addidng -90 give positive sign but these are things arbitart we have invented it. Special thanks for your effort and MRS BIEZEN THANK YOU SO MUCH FOR THE EDITING, AND PRODUCTION. lotos of love to both.

[fachriyasir]

sorry I'm new to this, but why should we change them to positive cosine form? can we change them to positive sin form?

[mohammadgholami]

Hello, thank you for your excellent teaching. I only had one question. In the figure on the top right, when we lower the cosine by 90 degrees, we reach the negative of the sine. Why did you write positively?

[sam-kxty]

To invert the negative amplitude of v1 why can’t we add a positive 180 degrees? Thanks as you reply .

[mayurambhore]

Thank you very much sir, I was facing so much problem while solving this type of sum