Like charges repel each other and unlike charges attract. An electric charge experiences a force whenever it is placed in an eletctric field. Electric field is a vector quantity. The direction of the electric field is the direction of the force on a positive charge when placed in the field. When a charge q is moved in a electric field, work must be done.
Electric potential is a scalar quantity.
This is a device for producing very large static voltages. Click here for a sketch of a VDG generator, and here to see a photograph. The electronic charge is one of the seven fundamental constants. It was first measured accurately by Millikan in 1917. He studied the motion of small charged oil drops first under the action of gravity and then when an electric field was applied.