Surge protection device (TXU3 SPD) is also called surge protector, is used to limit transient overvoltage and leakage protection devices on the guidance of nonlinear surge current of charged system, to protect the low voltage level of electrical or electronic systems against lightning and lightning electromagnetic pulse or operating over-voltage. In recent years, the rapid development of electronic information systems (such as television, telephone, communications, computer networks, etc.). This kind of system and equipment is more expensive and important, its working voltage, voltage level is very low, very vulnerable to lightning electromagnetic pulse harm, for this need to use SPD as over-voltage protection.
Classification of surge protective devices
SPD is an indispensable device of lightning protection of electronic equipment, its function is to enter into the instantaneous power lines, signal transmission line overvoltage can withstand voltage range in the equipment or system, or a powerful lightning flow into the earth to protect the protected equipment or system is not affected by the impact of.
According to the classification of the working principle, SPD can be divided into voltage switch type, voltage limiting type and combined type.
(1) Voltage switching type SPD. When there is no transient over-voltage, it presents a high impedance, once the lightning transient over-voltage, the impedance will change to a low impedance, allowing the lightning current to pass, also known as the "short circuit switching SPD".
(2) Voltage limiting type SPD. When there is no transient over-voltage, it is a high impedance, but with the surge current and voltage increases, the impedance will continue to decrease, the current voltage characteristics are strongly nonlinear, sometimes referred to as the "clamp type SPD".
(3) Combined type SPD. The utility model is composed of a voltage switch type component and a voltage limiting type component, and can be displayed as a voltage switch type or a voltage limiting type or both.
