Light-emitting diode UV LEDs for sterilization. LEDs have also been used as a medium-quality voltage reference in electronic circuits. The forward voltage drop (e.g. about 1.7 V for a normal red LED) can be used instead of a Zener diode in low-voltage regulators. Red LEDs have the flattest I/V curve above the knee. Nitride-based LEDs have a fairly steep I/V curve and are useless for this purpose. Although LED forward voltage is far more current-dependent than a Zener diode, Zener diodes with breakdown voltages below 3 V are not widely available. The progressive miniaturization of low-voltage lighting technology, such as LEDs and
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