Developer website: Paul Peters
Franklin is software for plotting electric field lines and equipotential surfaces around point charges. It is intended as freeware for science education. It is not, however, meant for commercial use or distribution without my permission.
Version 1.8 is now a Universal Application. It is however very similar to version 1.7. Some of it's features include:
- Field lines can be generated automatically from the action menu. The menu item "Random Lines" will generate 20 lines per charge. If the charges are of differing magnitude the number of lines emanating from a charge will be proportional to the magnitude of the charge but will still average to 20 per charge. The field lines will begin at random positions on small spheres centered on the charges. Because of the randomness of the field points the resulting plot may look untidy. For those desiring more control over field lines Franklin can now read in the staring points for these lines from the charge files it generates. This must be done from a separate text editor as described below but can give more pleasing results than random lines.
- Franklin can read plain text files containing coordinates to begin field lines. These coordinates must appear after the list of charge coordinates and be preceded by the words "field points" between angle brackets as field points. A few examples are included to show how this is done. It's important to remember that these field points can only be read. When a file is saved in Franklin only the charge coordinates are saved, not any field points that may have be previously read. To be safe one should therefore save these files as "read only" from their word processor of choice. How to generate the field points is a problem in itself. One way is to write a simple program that generates the list of coordinates and then copy and paste them into a charge file. Except for angle brackets other punctuation is ignored so things like commas are OK to use. Franklin will become unresponsive until all field calculations are complete so it's best to keep the lists on the short side.
Mac OS X 10.4 or later