Tiny little led sign illumination modules that operate directly at 220 to 240 volts to provide illumination and signage. But how do they do that? How do they drive three leds in these modules from 220 or 240 volts? Well, the answer is the ac gets rectified to dc. There's a linear current regulator and then they use three high voltage leds and two resistors in series to create the circuit that allows the leds to run on that high voltage. If you want more information, there's a longer video in the linked in the description and also with a link pinned at the top of the comments.