Ltspice question

Discussion in 'General Electronics Chat' started by Aleph(0), Nov 18, 2015.

  1. Aleph(0)

    Thread Starter Member

    Mar 14, 2015
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    So I post this in its own thread so not like hijacking HP's ltspice thread

    For series circuit of 25kv 30khz sinewave generator + 1nf cap + 10k resistor + ground
    I manually calculate and double check
    So Z≅10K+5305.2i rectangular form.
    So Z≅11.32k∠0.488 polar form (Sorry if ugly This my first time for symbol bar)
    So current should≅2.2085 amps but when I simulate with ltspice no matter how much I F#(% with cursor and magnifier I can't read more than 2.1872A:(

    I'm sorry about saying like crybaby on HPs thread:( I adopt her attitude now cuz I want to just learn so I bite back on negativity and just pay attention:) Tnx for help:)!
     
  2. crutschow

    Expert

    Mar 14, 2008
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    Can you post your .asc file?
     
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  3. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Indeed! -- @Aleph(0) --- Far be it from me to 'kibitz' - howbeit you really need to get on your ISPs backside in regards to easing your "VPN" restrictions! - Images really are worth much more than one thousand words and that goes double on these international fora... (OBTW - if 'flash' is indeed the problem, be advised that upload is possible without it -- though I ignore the details:oops:)

    Anyway... Give me a few minutes to construct a simulation based upon your text - While I'm honored that you asked me to have a look - you should know that I'm a knuckle-dragging neanderthal when it comes to Spice:oops::oops::oops: --- Back in a trice!:)

    Best regards
    HP
     
  4. Jony130

    AAC Fanatic!

    Feb 17, 2009
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    Set maximum time step at 10ns
     
  5. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Aleph, what can I say??? -- I see your point:rolleyes: (assuming the below pictured simulation is consistent with your circuit) -- FWIW your math looks good too...

    Best regards
    HP
    A0_ckt.jpg
     
  6. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    @Jony130 --- Sorry, I missed your response in the crosspost:oops:

    @Aleph(0) --- Get it? The simulator's default settings had it stepping too 'coarsely' and, hence, 'over' the 'crest' as it were... You may set the step interval in the simulation command dialogue...

    FWIW here are my results with my simulation of your (assumed) circuit... --- Although I didn't get fully to the calculated value - I think you get the point!:)


    a0ckt2.jpg
     
    Last edited: Nov 18, 2015
  7. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Addendum:

    @Aleph(0) Just a friendly heads up:)

    --Electronics application of "phasor notation" (and its ilk) prefers 'j' to 'i' for representation of the imaginary unit (Perhaps to avoid confusion with current - "I":confused:)
    --While I fully concur with your preference for radians -- Convention prefers degrees (outside of mathematical and abstract scientific settings) --- Yes! Yes! I know!!! It's counterintutive and downright bizarre!!!:rolleyes::rolleyes::rolleyes: --- Still, ease of communication can be nice too... Perhaps we're all masochists at heart?:D:D:D

    Best regards
    HP

    PS -- Now don't you become one of those folks who can't handle constructive criticism "when it happens":p:D:D:D
     
  8. Bordodynov

    Active Member

    May 20, 2015
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    See

    Meas_Ampl.png
     
  9. Aleph(0)

    Thread Starter Member

    Mar 14, 2015
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    HP it price I pay for free isp perk from VGH foundation but is ok cuz you guessed circuit right:)! HP I know all about custom of j for i and about degrees but I say right and wrong aren't a popularity contest! So like science is the body but math is immortal soul plus all that raises humans above other animal life so that's where I'm comfortable:cool:
    Tnx Jony! More rapid sample time did trick:)!
    Bordodynov I think you are showing me way to exactly measure maximum excursion but I can't totally understand:oops: Plz say more:) Tnx to everybody:)!
     
  10. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Jarring though it may be - utilitarian convention isn't entirely without merit!!!:cool::cool::cool:
     
  11. Bordodynov

    Active Member

    May 20, 2015
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    To calculate the amplitude of the current I used one hundredth period of oscillation.
    This is due to the fact that the established processes is obtained immediately.
    I showed with the new scheme the first period, and for the hundredth time.
    I also made a Fourier analysis.

    RC1.png
     
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  12. Aleph(0)

    Thread Starter Member

    Mar 14, 2015
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    Tnx Bordodynov:)! Could you plz upload the .asc for that so I can explore the ways of it without having to already know how to enter it all?
     
  13. Bordodynov

    Active Member

    May 20, 2015
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  14. Aleph(0)

    Thread Starter Member

    Mar 14, 2015
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    Thanks:)!
     
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