Light-emitting diode

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(wiki that discuss "throwies")
("What are the relevant parameters for a reverse-biased LED light sensor?")
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*[http://www.robotroom.com/ReversedLED.html Making an Amplified Color Sensor from an LED and an Op Amp]
 
*[http://www.robotroom.com/ReversedLED.html Making an Amplified Color Sensor from an LED and an Op Amp]
 
* [http://www.redrok.com/electron.htm#led1 LED1 LED Sensor Relay Tracker Schematic]
 
* [http://www.redrok.com/electron.htm#led1 LED1 LED Sensor Relay Tracker Schematic]
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* [http://electronics.stackexchange.com/questions/19051/what-are-the-relevant-parameters-for-a-reverse-biased-led-light-sensor "What are the relevant parameters for a reverse-biased LED light sensor?"]

Revision as of 22:42, 4 October 2011

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.

Contents

POV

POV display

throwies

Several other wiki discuss how to turn LEDs into "throwies":

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:

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