Example 2 - Solving for Step Response of an RC Circuit

[@electriccircuits7164]

The theory needed to solve this problem is discussed here: kzbin.info/www/bejne/qICXe4Bsjc9ljq8

[@engineermushfiq8147]

l got a lot of helping when I saw your video playlist.

[@electriccircuits7164]

Glad it was helpful for your learning!

[@talhajat3301]

damn this really cleared the picture for me, was so damn confused

[@electriccircuits7164]

Glad it benefitted your learning!

[@nadernaysak]

Very clear and explicit, THANKS!

[@electriccircuits7164]

Thanks for the feedback. Glad you liked it!

[@muhammedzaim]

hi, thank you so much for the explanation. very clear and easy to undersrand. can you share the " General steps to solve first order RC RL circuits" sheet you are showing in the video? will be nice to incoperate it in my notes. thank you.

[@electriccircuits7164]

Thank you for suggestion and sorry for the delayed response. These step are now added to the Video description.

[@anantsharma6720]

Great Explanation!!

[@electriccircuits7164]

Thank you for the feedback!

[@carlwong5084]

awesome video! thanks so much!

[@electriccircuits7164]

Thank you for the feedback!

[@emreozturk305]

thanks! great explanataion

[@electriccircuits7164]

Thank you for the feedback!

[@akifrezan8381]

Hye i would like to say thank you so much!!very grateful found this video its help me a lot

[@electriccircuits7164]

Thank you for the feedback and glad it was useful for your learning!

[@arastraninsan9798]

does not it supposed to be Vc infinity - (-75)? due to polarities and then we find Vc infinity = 100v

[@electriccircuits7164]

Thank you for the question. The value calculated in the video is correct. VC Infinity cannot be 100V. After switching has occurred there is only the 75V source in the circuit. So a long time after switching has occurred the voltage across the capacitor cannot exceed the source voltage. We have some resistors so some voltage is dropped across them. Thus vc Infinity magnitude is less than the source voltage. I hope this intuitive argument explains why your reasoning is incorrect and VC Infinity cannot be 100V.

[@arastraninsan9798]

​@@electriccircuits7164 what about polarities? positive side of the 75v voltage source is referred to as ground, that is, 0 v so, we need to accept other side of the 75v voltage source which is negative side as -75v. Am I wrong?

[@kunjupulla]

Exactly bro I am having the same doubt. Did you do this question from some other source where they took the polarity as +75V?

[@talhajat3301]

what do you do if there is a dependent source?

[@electriccircuits7164]

Thank you for the excellent question. The systematic approach discussed in this video does not apply if the RC circuit contains a dependent source. For such circuits, one must resort to the method of writing and solving the differential equation. This is because if an RC or RL circuit contains a dependent source, then there is the possibility of unbounded response, i.e., voltages and currents increasing without limit. Thus, we cannot use the t =0-, 0+ infinity analysis to predict the final value of the voltage or current.

[@Harry001by7]

What if any of the dc source replaced with a period signals like square wave say its -0.7 to 4.3v and whose frequency varying around 350kHz to 500Khz. Thanks in advance

[@electriccircuits7164]

Thank you for your question. The technique demonstrated in this video works for DC sources only. For periodic sources, you would need to use Fourier or Laplace transform to solve the circuit.

[@shalom1101]

How come you got Vc(infinity)= -60 instead of 60?

[@electriccircuits7164]

Thank you. It is because of the polarity of the 75 V source with respect to the ground. Hence, we solve and get -60V and not +60V.

[@Professor_el]

do you also have videos about sequential switching in these rl and rc circuit??

[@electriccircuits7164]

Thank you for the question. Sequential switching is when the energy storage element (C or L) is only allowed to partially charge or discharge as a result of switching taking place. The available videos in this channel at the moment consider cases when C or L is allowed to fully charge/discharge. Sequential switching can be easily simulated using the techniques discussed in the channel videos. I will take your suggestion on board and consider theory/examples of sequential switching in future videos.

[@Professor_el]

can you please post unbounded response too

[@electriccircuits7164]

Thank you. I will consider this in future videos.