Timeline for LTspice value of peak current and theoretical value in a circuit question
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Jan 17 at 13:54 | answer | added | Jan Eerland | timeline score: 1 | |
| Jan 15 at 4:12 | comment | added | Nero | @periblepsis I just started AC circuits, so my use of simulators was limited to DC and it was always lines and matching exactly with theoretical results; thus, I did not know in AC that it uses many approximations, and will try to turn off the lossy compression. Thanks a lot! | |
| Jan 14 at 23:36 | comment | added | periblepsis |
@Nero From your own chart, you can readily see that it is a numerical problem. Those straight-line segments there on the curve tell you explicitly where the points are calculated. And it's starkly obvious that there isn't sufficient data to fill in where you need it. Even with the added missing samples, LTspice also automatically (by default) compresses the data, too. (Lossy compression.) You can turn that off with a .OPTION PLOTWINSIZE=0 card. And Spice programs take many shortcuts. In short, don't expect perfection when running simulators. That is expecting too much from them.
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| Jan 14 at 15:45 | comment | added | Nero | This actually made it closer ~1.08mA. Thanks @G36, now I see that it is due to the timestep. | |
| Jan 14 at 15:37 | comment | added | G36 |
The simulation time step is too low. Try to increase the maximum timestep to 1us. Change tran to .tran 0 0.8 0 1u
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| Jan 14 at 15:29 | comment | added | Nero | Just wanted to add, yes indeed, when I tried stimulating circuits with very small capacitance and inductance, the numbers were extremely close to the theoretical value. But, as the values increase, there is a significant difference. | |
| Jan 14 at 15:29 | comment | added | Nero | Ohh first ime I notice that It wrote 1mOhm by default, thanks! Now I tried putting SR = 0 when right clicking on the inductor and trying but approximately the same value ~1.05mA. | |
| Jan 14 at 15:13 | comment | added | Rohat Kılıç | LTspice puts a 1 mOhm DCR (DC resistance) in series with the inductors, if you don't specify. Can't remember at the moment but there must be a similar thing for the capacitors as well (ESR). I'm not sure if you can put 0 (zero) but at least you can try with much lower numbers (e.g. 1p). There are also parallel resistors, although they are really big they may or may not show a substantial effect. | |
| S Jan 14 at 14:55 | review | First questions | |||
| Jan 14 at 15:56 | |||||
| S Jan 14 at 14:55 | history | asked | Nero | CC BY-SA 4.0 |