Abstract: A surge protection device detects whether a surge voltage occurs at a power input port by using a first Zener diode and a second Zener diode. When the power input port receives a normal voltage, the surge protection device turns on a first transistor to transmit the normal voltage to a load. Otherwise, when the power input port receives the surge voltage, the surge protection device prohibits the first transistor from conducting so as to protect the load from being damaged by the surge voltage. The surge protection device protects the load by controlling conducting or not of the first transistor and is manufactured without a surge protection unit. Therefore, manufacturing cost of the surge protection can be decreased.

Abstract: A surge protection device detects whether a surge voltage occurs at a power input port by using a first Zener diode and a second Zener diode. When the power input port receives a normal voltage, the surge protection device turns on a first transistor to transmit the normal voltage to a load. Otherwise, when the power input port receives the surge voltage, the surge protection device prohibits the first transistor from conducting so as to protect the load from being damaged by the surge voltage. The surge protection device protects the load by controlling conducting or not of the first transistor and is manufactured without a surge protection unit. Therefore, manufacturing cost of the surge protection can be decreased.