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ra3xdh / qucs_s

Qucs-S is a circuit simulation program with Qt-based GUI
https://ra3xdh.github.io/
GNU General Public License v2.0
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parameters not working in rectangular voltage source #819

Closed bobu01 closed 3 months ago

bobu01 commented 3 months ago

In the rectangular voltage source component, some values don't work when using a parameter value. U, U0, Tr, Tf, Td do work. TH and TL do not work. No error message is generated. A parameter like {value} seems to cause a zero pulse width in the .cir netlist. There are similar issues with T1 and T2 in the voltage pulse component.

Please see the zip file for examples. rect_src.zip

System is an up to date Arch Linux distro. qucs-s version is 24.2.1

ra3xdh commented 3 months ago

It is not a bug. The rectangular voltage source has different definition of parameters in different simulator. The SPICE requires PER=TH+TL, but Qucsator requires TH and TL separately. Qucs-S GUI have to calculate the PW for SPICE from TH and TL. This cannot be done without conversion of the parameters in numeric form. So the variables in TH and TL are not allowed for SPICE mode. Use the red V source and define the full SPICE string if you need variables.

ra3xdh commented 3 months ago

I have made some tests and found that Ngspice accepts expressions inside the PULSE source definition. So, the variables for TH and TL parameters could be allowed. I will add a fix for this soon.

bobu01 commented 3 months ago

Thank you

ra3xdh commented 3 months ago

Fixed by #825 image