Author Topic: Id appreciate input about this RC circuit. Thank you so much :D ! !  (Read 229 times)

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Offline renzoms

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So I got some results that are both correct at some time t and incorrect at other time t. What can you say about the results. The topic is in the bottom right in red.
 

Offline renzoms

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Re: Id appreciate input about this RC circuit. Thank you so much :D ! !
« Reply #1 on: October 19, 2019, 11:34:43 pm »
So I got some results that are both correct at some time t and incorrect at other time t. What can you say about the results.

I calculate the Voltage across C1 (V_C1) using a Thevenin EC. Then with that,

I got V_R1, I_C1, I_R1, I_Rs, V_Rs (everything on the left half.)

So then to calculate V_C2 and V_R2, I used 10 - V_Rs - V_C1 (method 1 "m1.")

With V_R2,  I got I_R2, henceforth I got I_C2.

So using m1 I got some weird results. 10V for V_C2 at t = 0 and -0.1 A I_C2 at t = 0.

I'd like to know if there is another way to get V_C2, without using another Thevenin EC.

And what do you think I should take away from this experience (the fact that there are correct and incorrect results for V_C2 and I_C2.)

Thanks like a lot.
 

Offline renzoms

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Re: Id appreciate input about this RC circuit. Thank you so much :D ! !
« Reply #2 on: October 19, 2019, 11:40:49 pm »
It's affecting my graphs of I and V of C1 and C2
 

Online rstofer

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Re: Id appreciate input about this RC circuit. Thank you so much :D ! !
« Reply #3 on: October 20, 2019, 01:30:29 am »
I just plotted the voltage of the second capacitor over a short time (to see the fast rise near t=0) and a long time to see the steady state.
Really, this is a 5 minute thing with LTspice

I added names to the traces and added a trace at the output of the 2 Ohm resistor.  The voltage across C1 is not plotted but it is simply the difference between the traces.
« Last Edit: October 20, 2019, 01:48:01 am by rstofer »
 
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Offline renzoms

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Re: Id appreciate input about this RC circuit. Thank you so much :D ! !
« Reply #4 on: October 20, 2019, 01:45:59 am »
Thanks dude!

I did a Thevenin equivalent circuit, solved it, and then was off by a factor of 10 somehow. I'm happy with the experience though. I appreciate the effort use LTSPICE and offer those graphs!
 

Online rstofer

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Re: Id appreciate input about this RC circuit. Thank you so much :D ! !
« Reply #5 on: October 20, 2019, 01:48:58 am »
Thanks dude!

I did a Thevenin equivalent circuit, solved it, and then was off by a factor of 10 somehow. I'm happy with the experience though. I appreciate the effort use LTSPICE and offer those graphs!
I changed them a bit.  I was going to add a trace of the voltage ACROSS C1 but it's pretty easy to see what it will be.

I attached a graph with the voltage across C1 specifically plotted.  Note that it charges quickly to some high voltage then drops over time.  This is a consequence of the 1mF capacitor looking like a low impedance for a relatively long time.
« Last Edit: October 20, 2019, 01:56:48 am by rstofer »
 
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Offline renzoms

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Re: Id appreciate input about this RC circuit. Thank you so much :D ! !
« Reply #6 on: October 20, 2019, 05:02:57 am »
Interesting! I'm very tired so I'm off for tonight. I found where that factor of 10 came from, so the circuit is solved :). Thanks again for sharing your graphs. I'll look at it tomorrow, again.
 


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