LEDs driven by AC without transformers or rectifiers

Robin W. Hughes, Mark Warner
2021 Scientific Reports  
AbstractWe explore the driving of LEDs by untransformed AC. An extreme case is driving 1.9 V threshold (red) LEDs with UK mains, peak voltage 325 V. Commonly, driving is by transformed, rectified (DC) supply with a series resistor (where a significant fraction of the power is wasted) to limit current in the LED. With AC, one can instead reactively limit to a maximum current safe for an LED by employing a series capacitive impedance. Cheaper and simpler supplies can thus be employed in some
more » ... ployed in some cases. We analyse such non-linear circuits, and also explore questions of duty cycle and power experimentally.
doi:10.1038/s41598-020-80617-2 pmid:33441881 fatcat:o2syex5mz5f7zeafum7gucvvfa