Light is made up of photons which are, in simple words, packages of energy. An excited electron releases photons. The color of the light depends on the wavelength, which in turn depends on the energy released by the electrons.

With Edison's light bulb, mankind moved from candles to electric light. The electric bulbs ruled for nearly a hundred years. The general light bulb consists of a tungsten coiled filament, inert gas, the glass mount, electric contact and the housing which keeps all intact. With the electric current, the electrons in the atoms are raised to a higher energy level. When they fall back to their normal levels, the extra energy in the form of photons is released by the electrons .When heated with the electric current, the metal filament emits visible light. The inert gas prevents a combustion reaction.

With the rise of semiconductors, LED bulbs become more popular. According to the basic working principle of the diode, when the conduction band is made wide, the light emitted by diodes can be seen by human eyes. To create a large number of photons, LEDs are specially constructed to release electrons. Also, the plastic bulb in which the diode is placed helps concentrate the light in the desired direction. The sides of the bulb make most of the light from the diode bounce off and travel on through the rounded end of the bulb.

The plus point is that LEDs do not contain any filament. LEDs are more efficient than conventional bulbs with filaments. The average life of an LED is up to 10,000 hours. They are more durable and more resistant to blows or shocks. LEDs require less power; hence less battery is consumed than with conventional bulbs. The energy wasted is minimal with LEDs.

The negative point is cost. As they are made with advanced semiconductor technology, the cost is more than for conventional bulbs. But again, long running capacity and durability give LEDs the upper hand.