This slide shows the current/voltage curves of a varistor and a Nexperia ESD diode before and after one ESD strike. In the left hand graph, the varistor current/voltage graph after an ESD strike, red curve, shows that performance is clearly degraded in comparison to the black curve before the strike. This degradation, after only one ESD strike, in all probability leads to unwanted behavior of the circuit or even to complete failure. On the right hand graph, the Nexperia ESD diode shows no degradation of the current/voltage curve and therefore the functioning of the circuit is not hampered.