LED light bulbs – How do they work?

If you care about saving energy (or saving the environment) or you just want to save your money, you should take interests in LED light bulbs. Well, I assume you know what an LED (Light Emitting Diode) is; a semiconductor PN junction device which emits light when supplied with DC power. This article is about, LED light bulbs or LED lamps which already have started replacing CFL bulbs. This article answers how does an LED light bulb work and also explains the benefits of LED bulbs over CFL bulbs.

How do LED light bulbs work?

An LED is a tiny semiconductor device which emits light. LEDs are actually very small solid light bulbs which are extremely energy efficient. They have been around us from many years. The most familiar example of an LED can be given as the “LED flash that your mobile phone probably has”. It is clear that even a tiny LED can give much amount of light. But, that’s not enough to light up your whole room. A single LED can not fit into the standard light fixture. Moreover, an LED needs DC supply, but AC supply is standardized everywhere. An LED light bulb is manufactured to fulfill all your needs. The following image shows a dismantled LED light bulb.

inside an LED light bulb

  • Bulb shell is typically made up of plastic and designed in such a way that it spreads the light evenly.
  • LED panel is a small PCB which houses many LEDs electrically connected to each other.
  • Driver circuit converts the AC power supplied from the mains into the suitable DC power (usually, 12 V DC). The driver circuit is essentially a rectifier and regulator circuit which feeds the LEDs. During the operation, the driver circuit produces some heat which must be dissipated.
  • The generated heat is dissipated by the heatsink. The heatsink is usually made up of aluminium fins and designed such that it radiates heat away from the driver circuit. It also acts as the housing for the circuit and LED panel.
  • The connector base is made according to the standard/popular light fixtures in a particular country, so that you won’t have to change your existing light fixtures.

Advantages of LED light bulbs over CFL and ordinary bulbs

  • First thing you must note that the amount of light is measured in ‘lumens’ and not in ‘wattage’. Wattage is the unit of measurement of electrical energy. Ever noticed a 14 watt CFL bulb gives the similar amount of light as that of an ordinary bulb (incandescent lamp) of 60 watts? So, here efficiency means more lumens in less wattage. An LED bulb is even more efficient. A 9 watt LED light bulb can give the equivalent amount of light as that a 14 watt CFL bulb gives.
  • LED bulb gives more lumens in less wattage. That means it does not eat a lot of the energy and thus saving your money.
  • An LED light bulb lasts much longer than a CFL. The average life of an LED bulb is about 12000 to 15000 hours. Whereas, the average life of a CFL is about 6,000 hours and that of an ordinary bulb is about 1,000 hours.

So, even though an LED light bulb seems expensive when buying, it actually saves more money by saving energy and lasting longer.


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