The working principle of surge protector SPD

The surge protector SPD is indispensable to electronic equipment lightning protection in a device, its function is put into the power line, signal transmission line transient overvoltage limit in the device or system can withstand voltage range, or powerful lightning flow defined, protect the protected equipment or system from shock.

The type of surge protector and structure according to the different USES different, but it should contain at least one non-linear voltage limit element. Used for surge protector of the basic components are: discharge gap, gas discharge tube, varistor, suppression diode and choke coil, etc.

Type of electrophoretic protector SPD

According to the working principle of the classification, the SPD can be divided into voltage switch, pressure limiting and the combination.

(1) Voltage-switch typ SPD, presents high impedance when no transient overvoltage, once the response to the lightning transient overvoltage, the impedance change for low impedance, allow the lightning current, also known as the "SPD short circuit switch mode".

2) Voltage-limited typ SPD, when there is no transient overvoltage, as the high impedance, but with the increase of the transient current and voltage, the impedance will decrease continuously, its current voltage characteristic is strongly nonlinear, sometimes referred to as "clamp pressure type SPD".

(3) Combination type SPD, the voltage switch components and pressure limiting components, can be displayed as the limit of voltage switching or pressure or both some features, which depends on the characteristics of the applied voltage.