Changes

determine if switching occurs without arcing, results in a glow discharge, short instable arcs are generated, or a fully developed electrical arc is created. The more exact current-voltage curve characte-ristics are depending on the electrical contact material used. They also depend on the contact gap and the atmosphere the switching occurs in; an ambient air atmosphere is assumed in the shown schematic example.

For the different requirements on the electrical contacts in various applications it is useful to differentiate across the broad spectrum of possible load conditions guided by the arc-limiting graphs between four different partial ranges which result in typical physical effects: