Difference between revisions of "Light emitting diode"
From ScienceZero
(New page: ==Driving== The best method to drive a LED is with a fixed current. A LED can also be driven with an exact fixed voltage or an inexact fixed voltage that requires a series resistor to get ...) |
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The efficiency of a LED depends on the type but is comparable to a high efficiency incandecent lamp. A coloured LED can be much more efficient than an incandecent lamp because the LED does not need a coloured filter that absorbs all the unwanted colours. | The efficiency of a LED depends on the type but is comparable to a high efficiency incandecent lamp. A coloured LED can be much more efficient than an incandecent lamp because the LED does not need a coloured filter that absorbs all the unwanted colours. | ||
| − | [Category:Electronics] | + | [[[Category:Electronics]] |
Revision as of 09:12, 14 February 2007
Driving
The best method to drive a LED is with a fixed current. A LED can also be driven with an exact fixed voltage or an inexact fixed voltage that requires a series resistor to get the correct current. The series resistor can be calculated with this formula:
- <math>R_s = \frac{V - V_f}{I_f}</math>
Where Vf is the forward voltage drop accross the LED and If is the current through the LED. Both values can be found in the datasheet for the LED. For a red LED the typical values are 1.8V and 20mA.
Efficiency
The efficiency of a LED depends on the type but is comparable to a high efficiency incandecent lamp. A coloured LED can be much more efficient than an incandecent lamp because the LED does not need a coloured filter that absorbs all the unwanted colours.
[[[Category:Electronics]]
