Bleskojistky

Gas-filled surge arresters operate on the gas-physical
principle of the highly effective arc discharge. Electrically,
surge arresters act as voltage-dependent switches. As
soon as the voltage applied to the arrester exceeds the
spark-over voltage, an arc is formed in the hermetically
sealed discharge region within nanoseconds. The high
surge current handling capability and the arc voltage,
which is almost independent of the current, short-circuit
the overvoltage. When the discharge has died down, the
arrester extinguishes and the internal resistance immediately returns to values of several 100 MΩ.