I need a tool to calculate the value of an unknown component (R, L or C) in a known RLC circuit. I searched internet and found tons of simulation software but no such a solver software. What I am looking for is neither a new simulation software nor a circuit nodal analysis software that can be used to calculate nodal / mesh network currents & voltages.

It is possible to calculate a component manually in a circuit when the excititation and output functions (steady state or transient, may be specified for example in S domain or just by w) are expressed. Usually S domain (i.e. Laplace) is a method for that but... This calculation becomes complex to do it manually when the RLC network becomes complex.

Following circuit is a randomly designed just for an example (to show what kind of parameters we have, Please don't try to solve that!).

Here; first I assume the circuit has a solution (following one may not have).



Manually I would write values of parts in S form to obtain Z's (in R, 1/Cs, sL) and equate it Vo/Vin and try to solve what X (L2) is here. But I think there should be a software that can do this for me.

My purpose is solving undetermined values to generate equations for analysis of same circuit at different frequencies and obtain equations (linear/nonlinear) that can be solved. Numerical or analytical solutions are all welcome.

Does anyone know a software to solve those kind of circuits or at least a software to work with the resulting bulky equations?

 

If it was me, I’d do it in Excel myself because I’d be reluctant to trust a model I didn’t build. The model might be fine but it’s too easy to use a model for things it was not intended for.

 

If it was me, I’d do it in Excel myself because I’d be reluctant to trust a model I didn’t build. The model might be fine but it’s too easy to use a model for things it was not intended for.

Do you mean, doing an approximation by trial/error by writing the transfer function with the unknown as the parameter?

It will be still a large transfer function. I wish I had the solution in S-domain.

 

Do you mean, doing an approximation by trial/error by writing the transfer function with the unknown as the parameter?

I can't claim to understand the calculations you need to do, but yes, Excel can be used to iterate very quickly and converge on an answer to the precision level you desire. I do this all the time. It helps a lot if you can specify a good convergence algorithm. This usually requires knowing something about the function, such as its approximate slope.

 

This one can do symbolic analysis of a simple circuit, maybe you can give it a try. But it is very old, but you can still run it on Windows 7.

https://sourceforge.net/projects/xfunc22/?source=directory

 

I can't claim to understand the calculations you need to do, but yes, Excel can be used to iterate very quickly and converge on an answer to the precision level you desire. I do this all the time. It helps a lot if you can specify a good convergence algorithm. This usually requires knowing something about the function, such as its approximate slope.

I have also non-numeric (to be defined later) parameters in this circuit, thus I may consider numerical solution after I spent all my bullets in algebric solution.

This one can do symbolic analysis of a simple circuit, maybe you can give it a try. But it is very old, but you can still run it on Windows 7.

https://sourceforge.net/projects/xfunc22/?source=directory

I will check it, thank you very much.

 

This one can do symbolic analysis of a simple circuit, maybe you can give it a try. But it is very old, but you can still run it on Windows 7.

https://sourceforge.net/projects/xfunc22/?source=directory

Wow, it is an open source Borland C program, I remembered my school days. It needs to be worked on before telling something about it.

Thank you for sharing.

 

Wow, it is an open source Borland C program, I remembered my school days. It needs to be worked on before telling something about it.

Thank you for sharing.

Hi bkyavas,

You have to open the zip file, and get another zip file inside the zip file:
\XFUNC\XFBC\SOURCE\XFUNC22\EXEDISK\XFUNC22.ZIP

This zip file is where all the executable files are. Just run XFUNC.BAT to start. No need to work on Borland C. But you do need to run it under a Windows XP or DOS emulator. The Windows 7 just cannot take it anymore.