>> Yes, that's the other fun thing. Depending on which type of gates 
>> you're using, they supply about 20 mA. But some of the LEDs I'm 
>> looking it draw 40 mA...
> 
> What you mean is, they draw *up to* 40 mA?  How much they actually draw 
> depends on what value series resistor you put in there.  Using Ohm's law 
> and the V-I curve of the LED from the datasheet you can work out exactly 
> what resistor size you need for a given current.

See for yourself:

http://www.maplin.co.uk/Module.aspx?ModuleNo=35702

"Forward current: 25 mA"

If you can figure out what the hell that means, be my guest...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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