| asymmetric resistive two-terminal element characterized by zero voltage between the terminals when the electric current in it is directed from one terminal denoted A to the other denoted B and zero electric current when the electric potential at terminal A is less than or equal to the potential at terminal B
NOTE – The functional relation between voltage uAB and electric current i is:
uAB = 0 when i ≥ 0
i = 0 when uAB ≤ 0
where the reference direction for the electric current is from A to B.