Tuesday, November 23, 2010

Are LED Bulbs Worth the Price Part 1


Are LED Bulbs
Worth the Money

Regular readers will know that I had temporarily given up on LED bulbs as a viable domestic alternative. I had two reasons for this; (1) The very high cost of good quality LED bulbs running at around $35 each.  (2) The very poor quality of most of the cheaper alternatives.

Types of Light Emitting Diodes

LED bulbs use tiny individual elements or diodes to produce an intense light. The first LED made in 1962 was red coloured. In the early types of LEDs the diode elements were totally encased in plastic and were a small fraction of a millimeter in size.

It took a fair time for so called white light LEDs to be developed. The light produced is in fact very blue. To obtain white light of a nice natural colour involved introducing a yellow dye into the diode to filter the bluish colour and make it warmer in nature.

Types of LED domestic bulbs

Some domestic replacement LED bulbs use dozens of the tiny plastic diodes in order to produce sufficient levels of light.

Other types, based on more modern technology use larger high powered elements of up to several millimeters in size, sometimes mounted in multiples on the one die.

LED diodes of all types get VERY hot and need to be efficiently cooled or they will simply burn out or become otherwise damaged by the heat. Many will overheat and will turn blue to purple in colour and the light output will be greatly reduced by heat damage.

Good LED bulbs will have large aluminium finned coolers or "heat sinks" in order to carry away the excess heat. The crappy ones will not have metal fins to disperse the heat. These types of LED bulb will generally lose their light output, becoming dimmer and dimmer, and the light colour will turn bluish or purple in just a few months of working.

Any LED bulb that does not have sufficient cooling built in will not last "kissing time"  - I know, I have several duds in a drawer to prove it!!

More soon.


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