Light-emitting diode all the potential mechanisms that can induce failures in LEDs. The most common symptom of LED (and diode laser) failure is the gradual lowering of light output and loss of efficiency. Sudden failures, although rare, can also occur. Early red LEDs were notable for their short service life. With the development of high-power LEDs, the devices are subjected to higher junction temperatures and higher current densities than traditional devices. This causes stress on the material and may cause early light-output degradation. To quantify useful lifetime in a standardized manner, some suggest using L70 or L50, which are runtimes (typically in
Whitefish Point Light had two unevenly spaced eclipses, and two flashes within every 20 second period. Putting aside questions of nostalgia, aesthetics, or appreciation for the engineering of a bygone era (as exemplified by the Fresnel lens), this iteration of lighthouse illumination was itself incredibly effective, and an endangered remnant of another bygone era. The station was automated in 1971. In 2011, the U.S. Coast Guard Local Notice to Mariners reported reduced intensity of the Whitefish Point light from June 7, 2011 until August 16, 2011, when the DCB-224 Series Carlisle & Finch aerobeacon lens was changed to a light-emitting diode (LED) lantern