orcad is the commercial classic for doing schematics with a spice backend. (spice is an oss engine out of berkeley for simulating circuits on computers. for dc it just solves the classic nodal analysis and for ac you can feed in things from a fantasy signal generator and capture things at various nodes in the circuit) there's also some pretty cool looking commercial web thing now that also will maintain netlists with real-time prices and will let you swap parts out and set minimum quantities etc.
kicad is the oss orcad, but i never got good at it. (to be fair, orcad was weird to learn as well)
kicad is the oss orcad, but i never got good at it. (to be fair, orcad was weird to learn as well)