where cn i get free pspice program online???
I don't think you can get PSpice for free.
However, you can get LTSpice for free. It's also sometimes called SwitcherCAD or SwCAD.
Here is the URL for the free evaluation version for Pspice 8. It's the one I like best. It limits the number of components you can have but I've found it adequate for most of my designs.
There's a downloadable demo of PSpice which is free on the official software website. It should contain everything you need. PSpice is under Orcad now, by the way. I couldn't get the URL to work.
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