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Product Description

High voltage transients caused by lightning or other electrical disturbances have the ability to easily destroy semiconductor junctions, and thus, cause equipment failure. A lightning strike in the vicinity of data lines can cause induced ground currents which can also do serious damage. Typical leading edge wave-fronts of a lightning strike rise at the rate of 1,000 Volts per microsecond. The Model 22NX Lightning Sponge is designed to accommodate these transients, slow them down and redirect them to a low impedance path to earth ground.

RS-422/RS-485 is a low voltage, high speed interface. Protection of these RS-422/RS-485 lines is accomplished by using the 4-wire Model 22NX. It limits the voltage to approximately 7.5 Volts and passes signals whose data transfer rate can exceed ten million bits per second. The protection circuits incorporate 3 separate stages of limiting high voltage transients, gas tubes and two stages of avalanche diodes. The DC series resistance is limited to approximately 5 Ohms and the response time is measured in nanoseconds. It is good practice to install a Model 22NX on each end of the 4-wire transmission line.The output voltage is limited to ±7.5 volts for the Model 22NX.The Model 22NX provides 4-wire screw terminals on both ends for terminating the 4-wire lines. An additional screw terminal is provided to make the connection to earth ground. This wire should be at least #12 gauge or larger and be as short as possible. It will conduct the surge to earth ground (power ground or water pipe).

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