Thanks! Forward voltage there is too high (5V + about 2V dropout of
regulator). I'm looking for 0V (ideally).

Thanks!

Harold

> If you put a 5v 78L05 regulator across a resistor, it becomes a constant
> current device.  A pretty cheap way of doing it, maybe easier to get than
> a constant current diode.  You get the constant current, IIRC, out of the
> ground pin with the resistor connected between the ground pin and 5V pin.
>
>
> -- Lawrence Lile
> Lile Engineering
> Embedded solutions and industrial controls
>
>
>
>
>
> Harold Hallikainen <harold@HALLIKAINEN.COM>
> Sent by: pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
> 06/24/2004 03:37 PM
> Please respond to pic microcontroller discussion list
>
>
>         To:     PICLIST@MITVMA.MIT.EDU
>         cc:
>         Subject:        [EE:] Constant current diodes or FETs?
>
>
> I'm loooking for a two terminal constant current device that could be put
> between an LED and a variable DC supply to hold the LED current at 5mA as
> the supply varies over a 0-10V range (recognizing we're not going to get
> it at 0V, but I'd like the widest range possible). So far i've found the
> Central Semiconductor CCLM5750 which is a nominal 5.750mA, but it takes
> 4.5V to get 80% of the rated current. Anyone have other ideas?
>
> THANKS!
>
> Harold
>
>
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