Demystifying the Devices Behind the LED Light

We are almost always surrounded by light from LEDs in organic LED (OLED) TV screens and active-matrix OLED displays in mobile phone screens. LEDs are everywhere, in workplaces, headlamps, and stadium lights. They have gained immense popularity as power-saving, compact, durable, and sustainable alternatives to conventional incandescent and fluorescent lighting systems. But there is a catch: LEDs are unidirectional devices, i.e., based on dc supplies, while the primary power supply is ac. From this comes a mysterious component hiding in plain sight: the LED driver circuit, which enables the smooth operation of LEDs with dc and ac sources.