Mr. Electric!
Griffiths chapter 2 visualizer
This is an interactive simulator of Electrostatic fields. The main purpose behind this is to act as a tool to help check results from calculations, and also to visualize electric fields.
Check Guide for a more in depth explanation on using the simulator to help check your work. It runs in the browser, but can also be downloaded and run through any python IDE.
This is still a work in progress! As time goes on, the field will grow more dynamic, more interesting, and features will grow more diverse.