# Voltage source (DC) The DC voltage source of videomodels represents in 3D the behavior of the linear circuit theory DC voltage 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 DC voltage source is a dipole which imposes a constant voltage at its terminals, ideally whatever current therethrough.

The usual symbol of the DC voltage source is taken on the left figure below. DC means direct current.

We propose a 3D symbol representing the source (right figure above). This symbol has a long red bar to the highest potential and a short bar black for the lowest potential. The color choice is justified by the fact that in electronics, red is traditionally the color of the positive potential while black is the ground color (GND = 0V). Note that the color of the negative potential is blue, not used on this page.

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

• Modify source voltage by clicking it.

Possible values ​​are 0V, 1V, 2V, 3V

• Modify resistance value by clicking on it.

Possible values ​​are 1Ω, 2Ω, 3Ω, Inf (infinity, equivalent to the absence of resistance or open circuit). What is :   Plenty of information available on the Internet for voltage sources. A basic reference : ## References

Voltage source. Wikipedia.
http://en.wikipedia.org/wiki/Voltage_source