Two masses coming into contact and the separating can transfer electrical charges between them so that while before contact they were electrically neutral, after separation they are charged in opposite polarities.

A familiar example is that a person walking on a carpet made of high electrical sensitivity material may be charged to a high electrical potential (~10kV).

When this person comes into contact with an electrical circuit a path may be formed for the discharge of the stored electrical energy. The rise-time and peak magnitude of the current that flows under these circumstances are capable of causing damage directly or by induction to sensitive components.