How LED Light Bulbs Work

This post is exclusively for those who have studied physics with great interest during their schooling days. Rest, beware of the scientific lingo used herein.

LED or the Light Emitting Diode used for domestic and commercial lighting is a revolutionary technology in the sense that it is “solid-state lighting” or simply SSL. This is so since it does not use vacuum like the incandescent bulbs or gases like the fluorescents but emits light using only solid-state matter which is a semi-conductor. The technology is very simple; the light is created and emitted in an LED lamp due to the movement of electrons in the provided semiconductor structure.

Coming to the semi-conductor, it comprises of two components, one with a +ve charge and the other with a –ve charge. The negative layer of the semi-conductor has electrons floating around it and the positive layer has holes or openings for electrons. Once a forward electric potential is given across the semi-conductor, the electrons begin to flow from the –ve layer to the +ve layer. The flowing electrons combine with the holes on the +ve layer. As this occurs, energy is released in the form of light that is emitted by the LED.

Now, taking that light out, to lightup a living space is what the LED bulb technology is all about. While the light is good and abundant at the electron level, the structure of the LED bulb is the bottle-neck where most of the light gets trapped inside.

LED light bulb manufacturers claim “lumens per watt” which essentially means the amount of light emitted per watt of electricity consumed. So, the challenge is no more an unconquerable one and as a result, LED bulbs have actually brightened up in the recent past due to innovative technologies. On the market today, there are LED bulbs that can replace a 60-watt incandescent bulb by emitting the same amount of light for only a fraction of the same power. So LED bulbs today, have evolved to become viable for basic domestic lighting needs. There are bigger versions too, however, price concerns on them still haunt the users for commercial spaces.


And in more ways than one, they have become much more viable. For example, a good quality LED bulb emits light equivalent to a 60-watt incandescent bulb using only about 7.5 watts of power that is a saving of 87.5%of electricity consumption.

And in one other way, less than viable – A standard quality LED bulb capable of emitting 60-watt incandescent light costs upward of Rs. 500 while the incandescent costs about Rs. 10, which is 50 times more investment.

Viability – Considering that you are paying Rs. 7 per kilowatt of power, your LED spotlight bulb will pay for itself in 1200 hours of use, which is about 150 days or 5 months. Also, you may need replacement for the incandescent every year, however the LED will last you about 15 years. Considering this, the bulb will save you Rs 18,000 (approx.) over its lifetime in terms of energy bills.

So, waiting for the LED bulb prices to reduce is a thought that wastes time. Even if the prices come down in the near future, you are actually paying more because until then, your energy bills will keep mounting.

Neha Wagh