graphs the spot diagrams of a newtonian telescope mirror. Programmed in Apple Computers Cocoa IDE using the C and Objective C languages.Franklin
produces nice 3D Contour
graphs of equipotential surfaces and allows one to place point charges in three dimensions. It is one of the few programs that treats equipotential surfaces as truly 3 dimensional instead of 2 dimensional closed curves. You can edit charges in a text window and save them in a text file. The graphs are drawn in a fairly large window (1000x800 pixels) and you may change the background and potential colors to suit your taste. Although there are probably quite a few electric field graphing programs around, I think the above features make Franklin different from most. On the other hand Franklin doesn't do some of the things common to these other programs such as drawing field strength vectors and automatically spacing field lines around the charges. These things aren't very important to me but if they are to you, one of these other programs may be more useful. I think Franklin would still be a good compliment to one of these other programs however.
None of these point charge graphing programs, including Franklin, are very useful for most real world electrostatic problems. One reason is that most real world problems involve continuous materials instead of point charges. But a more important reason is that most problems involve the application of voltages to boundary surfaces. These boundary conditions then guarantee a unique potential everywhere else. On a conductor the charges Arrange
themselves in a Manner
that produces the given boundary condition there.The actual arrangement of these charges isn't important in solving Laplaces equation Outside
the conductors, only the boundary conditions are needed. Except for the method of images I don't see how this sort of problem can translate well to a point charge graphing program.