DC circuit adopted by the DC circuit is a closed electric circuit made up of DC power supplies and resistance. In the DC direct current circuit, the formation constant of the electric field. Outside the power supply, positive charge flow from high voltage to low voltage by resistance, inside the power supply, power supply non-electrostatic effects, eliminate static electricity, arrived from a low voltage high voltage, and so on, form a closed line of current. So, in DC circuits, power's role is to provide constant electric potential over time, as a Joule of energy consumed in the resistance.
In simple DC circuits, electromotive force, resistance, current, and voltage between any two points in accordance with Ohm's law and concluded that the definition of electric potential. Complex network based on DC G.R. Kirchhoff's equations. It consists of nodes and loop current equation equation is in two parts, which pointed out that, for any node (the intersection of 3 or more than 3 branch), into and out of the current node and zero of algebra, which is required for stable conditions, the latter pointed out that