First Order Transient Circuits

[@adamsdarrellj]

I'm a student at Arizona State, and got a professor with a thick Korean accent. The text book sucks, too. Your videos are one of the few reasons I am passing EEE 202. Thank you so much for the videos, kind stranger :)

[@ferntheyoutuber9960]

Same my dude. Except my teacher is indian.

[@kelvinfeliciano]

It seems like you went CCW in your KVL eq. I dont understand why the equation is not -6-3/2+vc(0)=0 Base on the polarity you gave to the resistor. It looks like it is dropping voltage not rising when going in that direction.

[@reedjasonf]

Thank you for this video. You may have just saved my life in Circuit Analysis class.

[@MattySarv]

For t=0- If you treat the 9k and the 3k resistors as one 12k, then do a simple voltage divider between the 12k and 4k you get Vc(0) = 4.5 Volts in one quick step. That is Vc(0) = 6V * [12k/(4k+12k)]

[@mcmadpac2]

Finding the Thevenin Resistance from the capacitor, and then solving for the time constant would have been a lot easier imo.

[@AraujoMatt]

F Tjangnaka - Your logic is correct. However I'm free to choose the direction of the currents for setting up a KCL equation. Here I want to set the differential equation in standard form (with a plus). Also, In more complicated circuits we wont always intuitively know whether a particular current is entering or leaving a node. We choose a direction and when we've solved the circuit, if the current is negative, its opposite the direction we chose.

[@oshak96]

Thanks a lot man! I understand my prof, but you make it look and seem so easy. This makes circuits fun :)

[@brandonsmith6333]

Thank you very much for your time. This is helping me with my Circuits final

[@kongmunky5268]

@F Tjangnaka When you use KCL is best to assume currents leaving the nodes in all directions and they are all assumed positive unless you have a current source indicating direction in the opposite (toward the node)... Then it becomes negative

[@Shumayal]

I second with you Kelvin! The polarities in the resistor should have been reversed..

[@AraujoMatt]

Ahmad and Kelvin, right you are! The math is still correct, I just drew the polarities backwards.

[@freaky504]

Thanks a lot! Great video and explanation. But don't you think using the Laplace Transform would make life easier in solving differential equations for such examples or rather more complex circuits?

[@AmeyaK21]

Awesome work- really helpful!

[@KillaKam922]

Thankz bro...this video was DESPERATELY needed lol

[@samirsabdo]

why you are not using Tau=(R*C) for the constant it's a lot easier ?

[@filbert4640]

im unsure why when you took the KCL you assume that current in both direction is leaving the node ? logically speaking one should enter the node and one exits the node right ?

[@oqhr]

when you did the voltage division, why you did not include the the capacitor since in is in parallel with 9k and 3k ??

[@ashonrandall4840]

It would be great if you would define your variables. Some of the equations in my book look somewhat similar but many variables are different. I didn't really understand 90% of what was going on here.

[@burakb8708]

thanks for the explanation

[@alanx4121]

1.2 is just tau, the RC timeconstant.

[@Dhoyos7]

Thank you!

[@user-ht4ye7tf1w]

thank you thank you thank you

[@xxasifxx]

u r a lifesaver

[@droryud]

explains pretty much. thanks

[@sunnypoppi19]

why is .1mF=.1/k?

[@coreyhulse8226]

by k he means one thousand(think of when people say that they make 12 k they mean 12,000), so he really means .1 / 1000 as thats what the prefix mili means in the metric system. So if had .1 milliFarads then I have .1 * 10^-3 farads which is equivalent to saying .1 / 10^3 or even simpler: .1/ 1000 which he calls k.

[@ArshadKhan_-_-_]

why we use KCL for capacitor and KVL for inductor?????

[@seita9398]

I can't get it...

[@cokpot635]

good explanation,thx!!

[@KwanzorGaming]

@9:28 , there is only 1 mesh so why is there 2 currents?

[@natanl]

KCL Iin = Iout of any node, and there r two pathways conencting to the node

[@MoneyWicks]

I love u man

[@ahmadsuleimanmusa5788]

I think v(0) is 7.5

[@parkerflop]

+James Hochstetler (AUkeLover) Thanks, awesome explanation

[@ahmadsuleimanmusa5788]

*****​ u are right. Thanks

[@AcTommyX]

This is wrong. V_c(0) should be 6.0V not 4.5V, since it is the voltage across the 4k resistor and ground.

[@PURE100808]

You have been mistaken. Vc(0) is 4.5V. It is the voltage across the 3k and 9k resistors.

[@jinshikami7525]

Can anyone test this out and give feedback? Search: 'Circuit Solver' on Google Play.