Electrical Engineering: Ch 12 AC Power (3 of 38) Instantaneous Power: An Example

[@zuhairalsaffar7001]

Even though I don't see you but l told my friends that you are my teacher l hope l will meet you thank you so much

[@JanyLol-um6ft]

All students about engineering successful about your idea

[@MichelvanBiezen]

That is the coal. 🙂

[@Zuwwar]

Hi Michel. Why is the axis here "t" and not "wt"?

[@Festus2022]

In your equation for v(t) you have theta as (+30). In your equation for i(t) you have theta as ( -20). Does this mean the phase angle of the circuit is 50 degrees? Thanks a lot!

[@MichelvanBiezen]

Yes, the phase angle is the difference between angle for v(t) and i(t) Since v leads i, the circuit is an inductive dominated circuit and the phase angle is positive.

[@علاءالدينالعقاد-و3خ]

والله إنك زلمة طيب

[@MichelvanBiezen]

Thank you. The goal in life is to try to be. I am still working on it. 🙂

[@علاءالدينالعقاد-و3خ]

@@MichelvanBiezen Today I have a midterm exam in electrical circuits 2, and the doctor sent us this question last night, and I did not understand it, but I understood it from your explanation.. Thank you from Palestine - Gaza. ❤️

[@MichelvanBiezen]

Great. I hope you did well on your exam. Welcome to the channel! 🙂

[@علاءالدينالعقاد-و3خ]

@@MichelvanBiezen Yes, I passed the exam well, thank God. And the first question that came in the exam was this question in this video with a slight difference, as it did not give me the current equation, but it gave me the voltage and impedance equations, and I calculated the current and completed the solution normally. Thank you. ❤️

[@akno1471]

Big respect sir thanks

[@kannanr9016]

Super sir. One doubt sir the -152 represents reactive power?

[@MichelvanBiezen]

The instantaneous power varies between + 698W and - 152 W. It therefore represents the lowest instantaneous power.

[@kannanr9016]

@@MichelvanBiezen thank you sir...

[@TruthWillSF]

amazing

[@mechminsk3627]

The intantaneous power is not time dependent. The proof is given in this video.

[@4leafclover202]

It’s is time dependent isn’t it? because the voltage and current in an AC circuit depend on time, the instantaneous power must as well

[@mechminsk3627]

@@4leafclover202 voltage and current are rotating vectors but powers are stationnary vectors, they don't rotate.

[@4leafclover202]

@@mechminsk3627 i Don’t understand that but in the equation for instantaneous power we have the independent variable t for varying power. Doesn’t that make it dependent of time?

[@mechminsk3627]

@@4leafclover202 When you have P(1-cos2wt) + P(1+cos2wt) is this function dependant on time or not? For me it's not because cos2wt -cos2wt = 0.

[@yougoog1]

2:59, the instantaneous power as a function of time is given by p(t) = 273 + 425(754t+10). If you plot this function vs. time, as shown in the video, its value changes with time sinusoidally. It is not constant with time. Depending on the different time value, it’s value is different, so it is time dependent. Your time function example has two time dependent terms, they are exactly opposite to each other, if you simplify your example function, two terms cancels each other, so the final expression does not include any term that contains the time variable, so it is not time dependent, but the instantaneous power function is not like your example. It only have one time dependent term. There is no other time dependent term that is opposite to this term to cancel it. You cannot do any further simplification to get rid of that time dependent term, so the instantaneous power is time dependent.

[@tamaica7770]

Sir. Why the angle i subtract angle v ? I see alot of formulas show that angle v subtract angle i

[@guanhan898]

The sequence when subtracting does not matter, try it. That is because negative and positive angle gives the same value for cosine function

[@tamaica7770]

Guan Han they define lead or lag. I think v must be before i.

[@yaze_game]

@@tamaica7770 think of 30 degrees on the voltage and 50 degrees on the current. cos(20) is the same as cos(-20)

[@danaali5317]

اولللل omg 11 🙂

[@danielcoolahan3438]

Can you please come teach my degree?

[@danielcoolahan3438]

and thank you.

[@MichelvanBiezen]

I am already working more than full time, but thank you for the invitation. 🙂