突波保護器(Surge protection Device)是電子設備雷電防護中不可缺少的一種裝置，過去常稱為“避雷器”或“過電壓保護器”英文簡寫為SPD。突波保護器的作用是把竄入電力線、信號傳輸線的暫態過電壓限制在設備或系統所能承受的電壓範圍內，或將強大的雷電流泄流入地，保護被保護的設備或系統不受衝擊而損壞。

突波保護器的類型和結構按不同的用途有所不同，但它至少應包含一個非線性電壓限制元件。用於突波保護器的基本元器件有：放電間隙、充氣放電管、壓敏電阻、抑制二極體和扼流線圈等。

　　一、SPD的分類：

　　 1．按工作原理分：

（1）開關型：其工作原理是當沒有暫態過電壓時呈現為高阻抗，但一旦回應雷電暫態過電壓時，其阻抗就突變為低值，允許雷電流通過。用作此類裝置時器件有：放電間隙、氣體放電管、閘流電晶體等。
（2）限壓型：其工作原理是當沒有暫態過電壓時為高阻擾，但隨突波電流和電壓的增加其阻抗會不斷減小，其電流電壓特性為強烈非線性。用作此類裝置的器件有：氧化鋅、壓敏電阻、抑制二極體、雪崩二極體等。
（3）分流型或扼流型
　　分流型：與被保護的設備並聯，對雷電脈衝呈現為低阻抗，而對正常工作頻率呈現為高阻抗。
　　扼流型：與被保護的設備串聯，對雷電脈衝呈現為高阻抗，而對正常的工作頻率呈現為低阻抗。
　　用作此類裝置的器件有：扼流線圈、高通濾波器、低通濾波器、1/4波長短路器等。

　　2．按用途分：

（1）電源保護器：交流電源保護器、直流電源保護器、開關電源保護器等。
（2）信號保護器：低頻信號保護器、高頻信號保護器、天線保護器等。

Surge protection device is an indispensable device in the lightning protection of electronic equipment. It used to be called "lightning arrester" or "overvoltage protector" in English abbreviated as SPD. The function of the surge protector is to limit the transient overvoltage that penetrates into the power line and signal transmission line within the voltage range that the equipment or system can withstand, or to leak strong lightning current into the ground to protect the protected equipment or system. Damaged by impact.

The type and structure of the surge protector are different for different purposes, but it should at least contain a non-linear voltage limiting element. The basic components used in surge protectors are: discharge gap, gas-filled discharge tube, varistor, suppression diode and choke coil, etc.

1. Classification of SPD:

   1. According to the working principle:

 (1) Switching type: Its working principle is that it presents high impedance when there is no transient overvoltage, but once it responds to the lightning transient overvoltage, its impedance suddenly changes to a low value, allowing lightning current to pass. When used as such devices, the devices include: discharge gap, gas discharge tube, thyristor, etc.

 (2) Voltage-limiting type: Its working principle is high resistance when there is no transient overvoltage, but its impedance will continue to decrease with the increase of inrush current and voltage, and its current-voltage characteristics are strongly nonlinear. The devices used in such devices are: zinc oxide, varistor, suppression diode, avalanche diode, etc.

(3) Shunt type or choke type

　　 Shunt type: It is connected in parallel with the equipment to be protected, which presents a low impedance to the lightning pulse, and presents a high impedance to the normal operating frequency.

　　 Choke type: In series with the protected equipment, it presents high impedance to lightning pulses, and presents low impedance to normal operating frequencies.

　　The devices used as such devices are: choke coils, high-pass filters, low-pass filters, 1/4 wavelength short-circuit devices, etc.

  2. Classified by purpose:

 (1) Power protector: AC power protector, DC power protector, switching power protector, etc.

 (2) Signal protector: low frequency signal protector, high frequency signal protector, antenna protector, etc.