LED Lights: How do the colorful strings of lights used during Diwali automatically turn on and off? Understand the technology..

The countdown to Diwali has begun, and a festive spirit has taken over—from the marketplaces to our very homes. Once the cleaning is done, it’s time for decoration, and the heart of this decor lies in colorful, twinkling string lights. As evening falls and these lights are switched on across balconies and rooftops, the entire atmosphere transforms into something out of a magical world.

You may have noticed that these lights don’t just glow steadily; they flicker rapidly, dim and brighten gradually, or even appear to flow like waves of water. We simply plug them in and let them be, but have you ever wondered how these tiny LED bulbs "know" when and how to turn on or off? Let’s decode the technology hidden behind these shimmering decorations.

The "brain" of the string lights is hidden in a small box.
If you look closely at a string of lights, you’ll notice a small plastic box near the plug, featuring a button. In reality, this box acts as the "brain" of the entire setup—technically referred to as a "chaser circuit" or "controller." Inside this box, there is a printed circuit board (PCB) and a tiny microchip.

The electricity supplied to our homes is AC (Alternating Current), whereas the LED bulbs in these strings operate on DC (Direct Current). This smart box not only converts AC to DC, but its internal chip is also pre-programmed with various patterns—such as chasing, flashing, and twinkling. The chip regulates the flow of electricity, causing the lights to flicker or pulse in the way we see.

Creating a 'Waving' Effect Through Specialized Wiring
Decorative light strings (often called *jhalars*) do not consist of a single wire; rather, they are made of a bundle of three or four wires twisted together. The bulbs are not connected in a single, continuous line; instead, they are organized into distinct groups—or "channels." For instance, the first, fourth, and seventh bulbs might be connected to one wire, while the second, fifth, and eighth bulbs are connected to another.

This configuration is a hybrid of series and parallel connections. When a microchip sends an electrical current through one wire while cutting it off from another, some lights turn on while others turn off. When this process repeats rapidly—faster than the eye can perceive—it creates an optical illusion, making it appear as though the light is moving or "flowing." Furthermore, thanks to this specific wiring, if a single bulb in the middle happens to fuse, the entire string does not stop working.

From Conventional to Smart Lighting
In the past, there were decorative light strings that lacked a control box; instead, they relied on a special "master bulb." Inside this bulb, a bimetallic strip would bend when heated, breaking the electrical circuit and causing the lights to turn off. As the strip cooled down, it would straighten, reconnecting the circuit and turning the lights back on. However, this technology is now largely obsolete.

The Rise of Mobile-Controlled Lights
Today, "Pixel LED" and smart lighting systems have become highly popular. In these setups, each individual LED bulb contains its own dedicated microchip. These lights can easily connect to a smartphone app via Wi-Fi or Bluetooth. You can simply play a song of your choice on your phone, and the lights will "dance" in perfect synchronization with the beat of the music.

Disclaimer: This content has been sourced and edited from News18 Hindi. While we have made modifications for clarity and presentation, the original content belongs to its respective authors and website. We do not claim ownership of the content.