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LTspice 4 Trouble With Transient Simulation Reults

Pisancho

Apr 2, 2016
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Hi guys i'm a newbie here. I am trying to simulate a circuit to determine whether the theoretical time response is the same as that which is simulated from a graph and i believe it should but i get a very large difference in the theoretical and simulated result. I'm also not sure if my graph is correct as its my first time using this software. I have uploaded the circuit to be simulated and my graph which i really believe to be wrong. Any help would greatly be appreciated. Thank you. RC(1).png
 

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  • Q1 Capacitor.pdf
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Pisancho

Apr 2, 2016
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Apr 2, 2016
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Rs is 100 ohm, R is 820 ohm, The pulse is from 0 to 5 volts and the capacitor is 150nF
 

Alec_t

Jul 7, 2015
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Post your asc file, so that we can see the voltage source parameters and where you're 'Vout' point is.
 

Pisancho

Apr 2, 2016
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Apr 2, 2016
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Post your asc file, so that we can see the voltage source parameters and where you're 'Vout' point is.
I have sent it. It is telling me awaiting moderator approval which is weird haha
 

LvW

Apr 12, 2014
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Doing a TRAN analysis the most important parameter is the specufied (minimum) time step (time resolution).
I always would suggest to use AT LEAST 1000 points within the simulation time.
So - for a simulation time of 1 sec I recommend a minimum step of 1msec.
What was your choice?
 

Pisancho

Apr 2, 2016
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Apr 2, 2016
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Doing a TRAN analysis the most important parameter is the specufied (minimum) time step (time resolution).
I always would suggest to use AT LEAST 1000 points within the simulation time.
So - for a simulation time of 1 sec I recommend a minimum step of 1msec.
What was your choice?
Thank you for reply. I am new to this simulator and i followed an example tutorial on how to do it. Where do i find the time resolution?
 

Pisancho

Apr 2, 2016
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Apr 2, 2016
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Thank you for reply. I am new to this simulator and i followed an example tutorial on how to do it. Where do i find the time resolution?
I set T delay to 0, T rise to zero, T fall to zero, T on for 1 second, The period to 2 seconds and the number of cycles to one. Those were the only parameters he said to change.
 

Pisancho

Apr 2, 2016
7
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Apr 2, 2016
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I set T delay to 0, T rise to zero, T fall to zero, T on for 1 second, The period to 2 seconds and the number of cycles to one. Those were the only parameters he said to change.
And stop time to 2 seconds in the simulation
 

Alec_t

Jul 7, 2015
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LTspice doesn't accept zero for the rise or fall time and will substitute its own times (0.1 sec in your case, which is what your graph shows). Replace zero with a practical value, e.g. 1u.
 
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