English: Qualitative depiction of the electric-field lines between the fingers of a comb-drive actuator. There are four different types of fields that have a distinct impact on the actuation in the work-energy picture of actuation. The field lines that connect the vertical sides of the fingers (blue) and those that connect the top sides of the fingers (red) are associated with the component of the force that tends to align the fingers. Those that connect the top sides with the vertical sides (green), tend to disengage the fingers. The field lines that connect the top of the finger with the sides of its neighbors (brown) do not contribute to the actuation force.