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→Low and Medium Electrical Loads
Guided by empirically developed arc-limiting graphs, typical switching processes can be distinguished. As <xr id="fig:Arc_limiting_graphs"/><!--Fig. 6.1--> illustrates, voltage and current determine if switching occurs without arcing, if it 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.
<figure id="fig:Arc_limiting_graphs">
[[File:Arc-limiting graphs.jpg|right|thumb|Figure 1: Arc-limiting graphs (schematic) 1. Arc-less switching<br /> 2. Short instable arcs <br />3. Glow discharge <br />4. Full electrical arcs]]
</figure>
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:
