Brief introduction:
FA906/FA9-68 Protectors are inserted into the FT203/FA8-68 Protection Terminal Block respectively, forming the protection circuits, which can provide the following protection against over-voltage and over-current:
1. The surge voltage caused by lightning on or around the external line.
2. The short-time AC voltage inducted on external lines, when the power line, the power system or the electric railway system is broken down in the neighborhood of the external line.
3. The external line directly collides against a 220 V power line.
Each protector has test eyelet, which can coordinate with the special test plug to test the external line as well as the components inside the protector. 

Structure:
PTC+GDT+LED
PTC+SA+LED
IC+LED
Note: GDT – Gas Discharge Tube; SA – Semiconductor Arrester;
    IC – Integrated Circuit
                                                                                                 
Technical Specification:
Insulation resistance ≥1000MΩ
Contact resistance difference between a line and b line: ≤1Ω
Lower Voltage Limit:  GDT protector (100V/s escalating rate) ≥190V
SA protector (100KV/s escalating rate) ≥190V
Upper Voltage Limit:  GDT protector (100V/s escalating rate) ≤260V
(1KV/us escalating rate) ≤800V
SA protectors  (100KV/s escalating rate) ≤260V
(1KV/us escalating rate) ≤400V
Alarming current ≥2.5 A (virtual value), with responding time ﹤15 seconds