Declan Moriarty wrote:
> 
> Was it Elbert Smit who wrote on Thursday 31 October 2002 14:23:
> > Hello Tinco, Declan & others,
> >
> > They function as a digital switch, it is used for serial communication at
> > 9600 baud. But I don't understand why the specification defines a minimum
> > inactive current. As Declan stated, the transistor leaks only nA or pA and
> > not uA's. Minimum"On"-current for the diode is not clearly specified, so
> > there's where I lose the link to a mininum inactive current...
> 
> Could it be minimum diode current which causes no transistor current?

I would certainly guess the same. Instead of specifying a "minimum on"
current, they specify a "maximum off" current  - that's the only thing
that would make sense in this whole context....
In general I would expect the threshold for light emission from a
light emitting diode (almost independent of the color and material) to
be in the uA range: for low currents non-radiative recombination
processes dominate even in direct band gap semiconductors. Over a wide
range the light emission is then directly proportional to the forward
current (-> external quantum efficiency), before the light emission
saturates (that's just before thermal destruction...).

Uwe.
-- 
Author: Uwe Zimmermann
  INET: [EMAIL PROTECTED]

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