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 ...

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 ...