Since both loads generating the field have negative signs, each component of the resulting field vector is convergent, meaning it has a sense of approximation.
The modulus, direction and direction of this vector are calculated by the parallelogram rule, as illustrated in the figure.
In this example, the loads generating the resulting field have different signals, so one of the vectors converges with respect to its generating load () and another diverges ().
Then we can generalize this vector sum to any finite number of particles, so that:
These lines are the conventional geometric representation to indicate the presence of electric fields, being represented by lines that tangent the resulting electric field vectors at each point, therefore, never intersect. By convention, the power lines have the same orientation as the electric field vector, so that for fields generated by positive charges the power lines are divergent (sense of distance) and fields generated by negative electric charges are represented by converging power lines. (direction of approach).
When working with dimensionless generating loads, the power lines are represented radially so that: