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LTspice 4 Trouble With Transient Simulation Reults

Discussion in 'General Electronics Discussion' started by Pisancho, Apr 2, 2016.

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  1. Pisancho

    Pisancho

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    Apr 2, 2016
    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
     

    Attached Files:

  2. Pisancho

    Pisancho

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

    Alec_t

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    798
    Jul 7, 2015
    Post your asc file, so that we can see the voltage source parameters and where you're 'Vout' point is.
     
  4. Pisancho

    Pisancho

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    0
    Apr 2, 2016
    here you go
     

    Attached Files:

  5. Pisancho

    Pisancho

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    Apr 2, 2016
    I have sent it. It is telling me awaiting moderator approval which is weird haha
     
  6. LvW

    LvW

    604
    146
    Apr 12, 2014
    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?
     
  7. Pisancho

    Pisancho

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    Apr 2, 2016
    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?
     
  8. Pisancho

    Pisancho

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    0
    Apr 2, 2016
    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.
     
  9. Pisancho

    Pisancho

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    0
    Apr 2, 2016
    And stop time to 2 seconds in the simulation
     
  10. Alec_t

    Alec_t

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    Jul 7, 2015
    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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