XuFyaN said:
yes but why the voltage is in GigaVolts ?? it should be 0 ?? and it is under damping circuit
Welcome to the reality of simulation.
Simulators
lie because they are still only approximations of reality and not reality itself.
For the ideal circuit used in the simulator, this answer is probably exactly correct. Just as if you use a differential equation form of the circuit you'll get infinities in impulse and step responses!
But it's not a correct answer for the real world because of the approximation/idealization of the circuit model used the simulator
to represent the real world circuit are just that: representations (aka approximations).
All simulators of any type have this problem which why anyone who blindly trusts what a simulator tells them is simply a fool/idiot.
This also why mastering hand-calculations of circuit analysis is still just as absolutely essential today as it was in the days of slide rules and paper calculation. You have to understand the real circuit well enough to recognize when the simulator lying to you.
Your case here is only an unusually obvious case of that mismatch between simulation and reality. Usually it's much more subtle. Knowing about step and impulse responses, you would
expect these kinds of high voltages to occur
in an idealized analysis.
So the reality is that capacitors do have some leakage (parallel R with every C) and inductors do have resistive losses (series R with every L) and switches do not turn on and off instantaneous and do have series resistance/inductance when closed and parallel capacitance when open. If you change your circuit to incorporate these kinds of 1st, then 2nd, etc. order parasitics, you'll start to get more "realistic" results.
But you'll have a whole lot more parameters to worry about. Welcome to engineering. You either have to trade this or "know" what to ignore from what the simulator is telling you.
