White And Red Led
Posted 17 September 2004 - 03:36 PM
Posted 17 September 2004 - 04:57 PM
Posted 17 September 2004 - 07:53 PM
Posted 17 September 2004 - 08:56 PM
Edited by ThrustinJ, 17 September 2004 - 08:58 PM.
Posted 18 September 2004 - 02:35 AM
Posted 18 September 2004 - 02:38 AM
|"Why do the LEDs have to be the same color?"|
If you mix colors, say if you paralleled a red (~2.3V) and two blue (~3.5V), the blue LEDs would not light. Why's this? Because the electricity is going to take the easiest path it can to complete the circuit and in this scenario the red LED requires less energy, leaving the two blue unpowered and lonely. To fix this you would need to stick a resistor onto the leg of each LED to 'equalize' all of the LEDs. Note illustration:
To find the resistor you'd need for each LED, use the 'Single LED' portion of an LED calculator, type in the supply voltage, LED's voltage and 20mA for each LED and there you go. Now each LED will turn on and each will receive it's desired amount of power. Thanks to Mike Moorrees for pointing this out, "The resistors act like 'shocks' in a car, they give the power source some 'squish' and let each LED find its happy place (forward voltage)."
this is at the bottom of the tutorials page. go there for the picture.
Posted 18 September 2004 - 02:45 AM
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