Current source The current source of videomodels represents in 3D the behavior of the linear circuit theory current source.

The circuit theory allows to model each real component by a set of basic ideal components (or elements ) interconnected.
A two terminals component is called dipole . It imposes a relationship linking the voltage between its terminals and the current flowing therethrough.
In the important case of linear circuits, the dipole elements are only five:
element : at all times, the element imposes only :
resistance proportionality between voltage U and current I
capacitance proportionality between voltage U variation and current I
inductance proportionality between voltage U and current I variation
voltage source the voltage U (for any current)
current source the current I (for any voltage)

The current source is a dipole which imposes a given current regardless of the voltage at its terminals.

There are several symbols for the representation of the current source. Two of them are shown on the left figure below.

We propose two 3D symbols (having same meaning) representing the source (right figure above). These symbols include one or two gold rings, a pointed bar indicating the direction of positive current and a current cone whose magnitude and direction show those of the instantaneous current. A blue ring is located at the front of the cone.

Interactive figures below each show a current source supplying a resistor. These two figures are equivalent, only 3D symbols have a different appearance.
In these figures, you can:

• Modify current source by clicking it.

Possible values ​​are 0A, 1A, 2A, 3A, -1A

• Modify resistance value by clicking on it.

Possible values ​​are 0Ω, 1Ω, 2Ω, 3Ω (0Ω is a short circuit). What is :   References

Current source. Wikipedia.
http://en.wikipedia.org/wiki/Current_source