A varistor is
a voltage-dependent metal-oxide material whose resistance decreases sharply
with increasing voltage. The relationship between the current flowing through a
varistor and the voltage applied across it is given by the relation I = Ken
a voltage-dependent metal-oxide material whose resistance decreases sharply
with increasing voltage. The relationship between the current flowing through a
varistor and the voltage applied across it is given by the relation I = Ken
Where i = instantaneous
current, e is instantaneous voltage and n is a constant whose value depends on
the metal oxides used. The value of n for silicon-carbide-based varistor lies
between 2 and 6 whereas zinc-oxide-based varistors have a value ranging from 25
to 50.
current, e is instantaneous voltage and n is a constant whose value depends on
the metal oxides used. The value of n for silicon-carbide-based varistor lies
between 2 and 6 whereas zinc-oxide-based varistors have a value ranging from 25
to 50.
The
zinc-oxide based varistors are primarily used for protecting solid-state power
supplies for low and medium surge voltages in the supply line. Silicon-carbide
varistors provide protection against high-voltage surges caused by lightning
and by discharge of electromagnetic energy stored in the magnetic fields of
large coils.
zinc-oxide based varistors are primarily used for protecting solid-state power
supplies for low and medium surge voltages in the supply line. Silicon-carbide
varistors provide protection against high-voltage surges caused by lightning
and by discharge of electromagnetic energy stored in the magnetic fields of
large coils.
