That’s the reason for the vast versions of SPICE available now decades after the original was released, not all of which are as open or free as we might like. Qucs is a GPL circuit simulator.

With this software, you can set ranges for various circuit components ... However, we appreciate the free release of this powerful simulator that can give LTSpice a run for its money.

Qorvo's QSPICE now features rapid model generation for JFETs, MOSFETs, and diodes, improving circuit simulation efficiency ...

In GPS and wireless communication, a constant voltage is vital at a desired network branch. But how to achieve that? One can take a circuit, for instance.