Math
Physics

This java applet is an electronic circuit simulator.  When the applet starts up you will see an animated schematic of a simple LRC circuit. The green color indicates positive voltage.  The gray color indicates ground.  A red color indicates negative voltage.  The moving yellow dots indicate current.

To turn a switch on or off, just click on it.  If you move the mouse over any component of the circuit, you will see a short description of that component and its current state in the lower right corner of the window.  To modify a component, move the mouse over it, click the right mouse button (or control-click if you have a Mac) and select “Edit”.

The "Circuits" menu contains a lot of sample circuits for you to try.