Maximum DC reverse voltage = VR or VDC, the maximum amount of voltage the diode can withstand in reverse-bias mode on a continual basis. Ideally, this figure would be infinite. 5V and 3V but for green, blue, and ultraviolet the voltage is often above. The forward voltage is the voltage drop across the diode if the voltage at the anode is more positive than the voltage at the cathode (if you connect + to the anode). These devices are currently used in the fields of telecommunications and medicine and in industrial cutting and welding applications. Therefore, in order to be effective, an ESD protection device and method should preferably be implemented as a proactive measure, by preventing the over-voltage or over-current.