Working Principles Of Switching And Voltage-limiting Surge Protectors

Switching Type surge protective device

Its operating principle is that it exhibits high impedance when there is no transient overvoltage. However, in response to a lightning transient overvoltage, its impedance suddenly drops to a low value, allowing the lightning current to pass. Devices used in this category include: spark gaps, gas discharge tubes, thyristors, etc.

Voltage-Limiting Type surge protector

This type of surge protection device operates on the principle that it exhibits high impedance when there is no transient overvoltage. However, its impedance decreases as the surge current and voltage increase, resulting in a strongly nonlinear current-voltage characteristic. Devices used in this category include: zinc oxide, varistors, suppressor diodes, avalanche diodes, etc.