Difference between revisions of "Light-emitting diode"
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(LEDs used "in reverse": as light sensors (moved from sensors)) |
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| − | + | A '''light emitting diode''' is the most popular kind of [[optoelectronics]]. | |
To make the LED light up, you need a power supply (any voltage) and a resistor. | To make the LED light up, you need a power supply (any voltage) and a resistor. | ||
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You then connect a 190 ohm resistance in series with the LED to make it work. | You then connect a 190 ohm resistance in series with the LED to make it work. | ||
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| + | == POV == | ||
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| + | [[POV display]] | ||
== sensor == | == sensor == | ||
Revision as of 18:25, 26 July 2008
A light emitting diode is the most popular kind of optoelectronics.
To make the LED light up, you need a power supply (any voltage) and a resistor.
The resistance required is as follows: R = (U_power - U_led) / I_max
Example: a LED with voltage drop of Uled=1.2V and a max current of I_max=0,020A (20mA) to be powered by a 5V DC source needs:
R = (5-1.2)/.02 = 190 ohm
You then connect a 190 ohm resistance in series with the LED to make it work.
POV
sensor
A few people use LEDs in an unusual way: as sensors.
further reading
LEDs used normally: to emit light:
http://en.wikipedia.org/wiki/LED
LEDs used "in reverse": as light sensors:
