Useful links for visualizing vector fields:

Note: You need to have Java VM installed on your computer. Download from here. Get the offline version and install it.

• http://www.falstad.com/emstatic/

Here you can choose different sources (charges, currents, conductors) and plot

electric or magnetic field vectors, field lines, equipotential lines/surfaces, etc…

Go to here for full description and help.

• http://www.falstad.com/vector2de/

Again you can choose different electrostatic sources and plot field lines,

equipotential lines, see the movement of charges particles in the electric field, etc…

Click here and here for full description and relevant mathematics.

• http://www.falstad.com/vector3de/

This is the three dimensional version of the above applet (only electrostatic charges). Here is the full description.

• http://www.falstad.com/vector3dm/

This is the magnetostatic version of the above 3D applet (DC currents).

• http://www.sunsite.ubc.ca/LivingMathematics/V001N01/UBCExamples/Flow/flow.html

Here is a demonstration of the flow of a vector field.

• http://lectureonline.cl.msu.edu/%7Emmp/kap18/RR447app.htm

You can plot the field lines for 2 point charges of different magnitudes and polarity.

• http://scitec.uwichill.edu.bb/cmp/online/P10D/Hunte/Electric%20fields.htm

There are no Java applets here but you can find many worked examples on electrostatic field and

potential calculations, application of Gauss’ law, etc…

• http://math.la.asu.edu/~kawski/vfa2/

A complete vector field analyzer!

 

New! (Thanks to Mr. Saba)

Charge and fields (Flash): https://phet.colorado.edu/sims/charges-and-fields/charges-and-fields_en.html
Faraday's Electromagnetics lab (Java): https://phet.colorado.edu/sims/faraday/faraday_en.jnlp
Also look at these simulations: https://phet.colorado.edu/en/simulations/category/physics/electricity-magnets-and-circuits
 

Point Charge Repelled By A Charged Sphere: http://web.mit.edu/course/urop/8.emfields/Public/animations/DS.avi

Point Charge Attracted To A Charged Sphere: http://web.mit.edu/course/urop/8.emfields/Public/animations/asphere_W20.avi
and many others in MIT animations for electromagnetism: http://web.mit.edu/jbelcher/www/anim.html

 

Other stuff:

• http://mathworld.wolfram.com/DeltaFunction.html

More about the Dirac delta function

• http://wiki.4hv.org/index.php/Dirac_Delta_Function

• http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html

Information about atoms and electrons, energy bands, properties of metals and

semiconductors, quantum physics, and condensed matter. Look at the “Condensed Matter”,

“Quantum Physics”, and “Electricity and Magnetism” sections