From POTS to broadband applications, gas discharge tubes or GDTs offer reliable and effective overvoltage protection solutions. GDTs protect central office and remote access equipment against lightning, power switching, fault conditions with their robustness, ultra-low capacitance along with low insertion and return loss performance. This white paper outlines Bourns’ GDT device operation and provides crucial design information on the relationship between key electrical parameters and ramp and surge waveforms, how to define ramp and surge impulses and how GDT parameters change over its life.