English: A simple DC circuit consisting of a battery (V) and a resistor (R), showing the Poynting vectors (S, blue arrows) in the space surrounding it, as well as the fields it is derived from, the electric field (E, red arrows) and the magnetic field (H, green arrows). The Poynting vector represents the direction and magnitude of the power flow in the electromagnetic field (the length of the vectors shown here are not to scale; only the direction is being shown) In the region of space around the battery, the Poynting vectors are directed outward, indicating that power flows out from the battery into the electromagnetic field. In the region of space around the resistor, the Poynting vectors are directed inward, indicating that since the resistor consumes power, the power enters it from the field. On any plane (P) located between the battery and the resistor, it can be seen that the power flux though the plane is directed toward the resistor.