Circuit Simulation

The first thing that I need is a circuit simulator. I've run into a surprising amount of trouble here.

Lush Projects

http://lushprojects.com/circuitjs/

Haven't tried it yet, but it looks pretty good. Based on the Java one I used to play with.

Circuit Lab

https://www.circuitlab.com/

Ok, but the free version was very limited. Subscriptions are expensive $15/month (cheapest plan is fine for me).

QUCS

Desktop FOSS. I kind of liked it but it was a pita to use and after figuring out some very odd quirks, I started running into problems with it's simulation. Basic oscillator circuits would crash the simulator.

The other significant disadvantage is that there was very little support.

Spice

Tried a few variants. Extremely difficult to use, and I ran into the same issue as QUCS.

GNU CAP

No information

Roll-My-Own

How could I not consider this? Since the field is so sparse, I should consider contributing.

Were I to do this, my goals would be:

• Simple "bread-board" simulation out-of-the-box
• runs in browser
• sub-circuits and components
• real-world considerations that can be "turned on", temp, noise
• export to other standards, particularly board layout tools.

Sub Circuit

Nothing fancy here, useful both for add standard ICs and for abstracting circuits. A sub circuit has exposed wires (pins).

Components

A component is a class. It has some number of constant parameters and takes some number of circuit parameters. For instance, a resistor is defined by a resistance. During simulation, this value is constant. It has two pins and performs simulation calculations for them.