[sdiy] LED Drops

[Grant Richter]

You might look for a chip called a REF200 by Burr-Brown

http://focus.ti.com/docs/prod/folders/print/ref200.html

It contains a 100 microamp constant current source.

If you put it in line with any diode, it should show the diode  
forward drop voltage (at 100 uAmp), but limit the current to a safe  
level.


On Dec 9, 2007, at 3:02 PM, mike ruberto wrote:

> Ok this is cool, the catalog has alot of good info.
>
> LOL "WE PUT THE "DIE" BACK IN DIODE" That website is a trip!
>
> I want to build this circuit...
> http://www.jlmaudio.com/JLM%20Hybrid%20Opamp%20circuit.pdf
>
> but all I have is a green LED. It seems the green have a higher
> voltage drop than the red. So it looks like I'll have to play around
> with resistors or a combo of regular diodes.
>
> Thanks!
>
> Mike
>
> On Dec 9, 2007 2:52 PM, Tom Wiltshire <tom at electricdruid.net> wrote:
>> Mike,
>>
>> It seems to depend on brightness as well as colour. The Maplin
>> electronics catalogue has the forward voltage for each LED they sell,
>> and looking through that gives a pretty good overview.
>>
>> http://www.maplin.co.uk/family.aspx?
>> menu=1692&source=2003&MenuName=Optoelectronics&worldid=-2&doy=9m12
>>
>> I don't know any handy website that pulls this information together
>> though, sorry.
>>
>> Regards,
>> Tom
>>
>>
>> On 9 Dec 2007, at 19:13, mike ruberto wrote:
>>
>>> Does anybody know where I can find a chart showing the typical  
>>> voltage
>>> drops of the various colors of LEDs?
>>> Thanks!
>>>
>>> M. A. Ruberto
>>
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>>
>>
>>
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