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
Light-emitting diode In this case, the bond wire(s) are attached to the ITO film that has been deposited in the LEDs. The YAG phosphor in the LED's encapsulation compound is why white LEDs look yellow when off. Some LED light bulbs use a single plastic cover with YAG phosphor (remote phosphor) for several blue LEDs instead of using a diffuser and single chip white LEDs. Remote phosphor LED light bulbs may have behind the plastic cover a white plastic reflector. Others shape the remote phosphor as a dome, or sphere, and place it atop a single PCB containing blue LEDs; this assembly