Capacitor Equations Explained

Explains the static and dynamic equations that model a capacitor, using intuitive explanations of the electrostatic forces and the movement of charge.
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[@ImranMoezKhan]

Great presentation Iain! It's always good to think in terms of the accumulated charge. Back when I used to teach electronics tutorials, most students had a difficulty understanding why capacitors are considered shorts in high frequency AC (or even understanding where the frequency domain equation comes from! The link between the time derivative and Laplace variable isn't often very well explained in EE I think). I used to tell them to go back to how you showed the charges accumulating on the plates, and then imagine that we suddenly flip the battery, then allow the charges to accumulate again with the opposite polarity. Then flip the battery again and allow charges accumulate, then flip again, and so on. Doing it fast enough will make it appear like the capacitor has turned into a wire. And the rate at which we switch the battery (signal frequency), will determine how much "resistive delay" the capacitor has, so that's where the frequency term in the reactance equation comes from. The students would usually understand it intuitively from that.

[@iain_explains]

Thanks for your comment. It's a great suggestion for another video. I've put it on my "to do" list.

[@peterbulanyi1708]

Excellent presentation. Thanks!

[@iain_explains]

Glad it was helpful!

[@sevix5692]

Just wanted to thank you professor. You helped me pass my exams and I finally understood signals. It's pretty fun actually. Thank you very much from Poland!

[@iain_explains]

That's great to hear. I'm glad the videos helped you.

[@hollywoodmovieclips-telugu7360]

Yep! Great presentation

[@iain_explains]

Glad you liked it!

[@ARJ0711]

Very helpful 👍👌🤍

[@iain_explains]

Glad to hear that

[@tuongnguyen9391]

I hope that you could do a video that explain how ac current can run through a capacitor

[@iain_explains]

Thanks for the suggestion. It's on my "to do" list.

[@davichaves2108]

Excelente, professor. Diretamente do Brasil!

[@iain_explains]

I'm glad you liked the video.

[@georgepalafox5967]

Hey Professor! Happy New Years!! Execllent intuitive explanation! Q: if the capacitor plates distance is shorter, this will cause the electric field forces to pull more negative charge from the battery towards the bottom plate ? Is this correct?

[@iain_explains]

Yes, that's right.