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simple RC circuit

Sali

 Dear all,

Can some one help me to understand why the voltage at time zero drops to a value less than 1 V?

Please check the attached file.

Thanks, 

Parents

  •  Hi Sali,

     

    the simulator works properly in alll the cases you've shown, it just not delivered the results you expected. Ofcourse
    their might be bugs from time to time, but when something like this is happening it is a good idea to first question
    your expectations.

    The last netlist works as you expected since you've pprovided that nodeset to net04, forcing a DC solution onto the simulator. In all other cases the simulator has to find it's own solution. A capacitor is treated as an open when looking for a DC solution, since
    that won't work in your circuit  the simulator uses the "rforce" paramater and replaces the cap with a 1 Ohm resistor.  10 Ohm and
    1 Ohm in series with a 10V voltage source delivers exactly what you see  as starting point in the simulations.

    As circuit designer it is essential to understand your simulator as well as  having an expectations on the results and keep questioning both. 

     

    Regards,

    Marc

     

Reply

  •  Hi Sali,

     

    the simulator works properly in alll the cases you've shown, it just not delivered the results you expected. Ofcourse
    their might be bugs from time to time, but when something like this is happening it is a good idea to first question
    your expectations.

    The last netlist works as you expected since you've pprovided that nodeset to net04, forcing a DC solution onto the simulator. In all other cases the simulator has to find it's own solution. A capacitor is treated as an open when looking for a DC solution, since
    that won't work in your circuit  the simulator uses the "rforce" paramater and replaces the cap with a 1 Ohm resistor.  10 Ohm and
    1 Ohm in series with a 10V voltage source delivers exactly what you see  as starting point in the simulations.

    As circuit designer it is essential to understand your simulator as well as  having an expectations on the results and keep questioning both. 

     

    Regards,

    Marc

     

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