The classic capacitor failure mechanism is dielectric breakdown. The dielectric in the capacitor is subjected to the full potential to which the device is charged and, due to small capacitor physical sizes, high electrical stresses are common. Dielectric breakdowns may develop after many hours of satisfactory operation. Open capacitors usually occur as a result of overstress in an application. For instance, operation of DC rated capacitors at high AC current levels can cause a localized heating at the end terminations. The localized heating is. The following list is a summary of the most common environmentally "critical factors" with respect to capacitors. The design engineer must take into consideration his own applications and the.