# \##fixedsolver

**URL:** https://forum.plexim.com/tag/fixedsolver/459.md

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## [Why does a model works on PLECS fixed solver but not on variable-step solver?](https://forum.plexim.com/t/why-does-a-model-works-on-plecs-fixed-solver-but-not-on-variable-step-solver/755)

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**Author:** [@JustinXuereb](https://forum.plexim.com/u/JustinXuereb)\
**Replies:** 2\
**Last updated:** [March 21, 2020, 7:11am UTC](https://forum.plexim.com/t/why-does-a-model-works-on-plecs-fixed-solver-but-not-on-variable-step-solver/755 "2020-03-21T07:11:39Z")

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I have a circuit based on the principles of resonance and with a fixed solver it works and with a variable solver it does not. Any help please?