> 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...

Load up the actual PDF spec that is linked from that page, it has more 
detail, just stating the forward current like that means nothing.

On page 3 there is the "Absolute max" table, the continuous current here is 
listed as 20/25/30 mA depending on the colour.  That is the maximum, above 
that they do not guarantee the LED will work.

On page 2 you see they've done all the spec values at 20 mA forward current.

Now look at the lower part of page 3, some interesting charts there 
(assuming the Bright Red colour, the others are on the next pages).

The one in the top right shows "brightness" against current.  You see it's 
linear up to 10 mA and then flattens out.  This is saying there isn't much 
point using more than 10 mA, it won't be very efficient.

The one in the top left tells you what current will be drawn for a 
particular voltage across the LED.  If you want 10 mA then you're going to 
need to give the LED 2.1 V.  You also see here that even adding just 10% to 
that voltage makes the LED current almost 3x higher!

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