In the very late 1990s, something amazing was invented. White LEDs. These magical pieces of semiconductors first became commercially available in 1996, and by the early 2000s, you could buy a single ...

Here’s a picture of an LED night light I picked up recently at Home Depot., and as you can see its light source is 3 white 5mm LEDs, which are are the little plastic domed LEDs more commonly used as ...

Described is one USB-chargeable Emergency Inspection Light for in-lab use, wired around a hi-efficiency 5mm-white LED. The power-bank of this circuit is a 1F/5.5v (yes, 1 Farad!) super capacitor. Just ...