Instructions
1. To add a charge to the palette, click on "Add a Charge", then choose the charge
value from the "charge" choice list, and position the charge on the palette by mouse clicking
on the desired location.
2. To draw an equipotential or field line, choose which type to draw, and the sense with which it is to be plotted, and click on the position of its starting point on the palette. Two thousand points will be drawn, it may not be enough to complete a closed-path equipotential, so you can finish the curve by changing the direction of the drawing, or clicking on the curves endpoints. You can change the color of the line as well with the "Color" choice box.
The algorithm used will accumulate errors in regions of high field strength, causing some curves to spiral, or not meet up at the endpoints.