Re: Correcting a LED response curve?
- From: "sycochkn" <sycochkn@xxxxxxxxxxxxx>
- Date: Fri, 14 Mar 2008 21:14:21 -0700
"Jacques St-Pierre" <multelec@xxxxxxxxxxxxxxxx> wrote in message
news:MUuCj.88491$w57.12441@xxxxxxxxxxx
I am designing a product using a Vactrol (led controlled resistor) to
simulate a RTD. The led intensity will be control by the buffered output
of a D/A chip. It is working, but to be useful, we have to operate the
led in the worst region of it's curve, resulting in very coarse response.
Since I do not have enough resolution on this D/A to correct that from
software I am searching for a method to render the Vactrol response a bit
more linear. Any one can suggest a simple way to create a amplifier using
a simple opamp or transistor to reproduce the reverse curve of the led
and correct the Vactrol response. I tough that maybe using a led in the
feedback path of an opamp may result in a non linear amplifier response
and that can be use to drive the Vactrol. Any suggestions?
Sorry if I offend anyone using the Vactrol name for the device. Since I
did not know of any other similar device, I tough using Vactrol should be
clear enough, but yes it's a "LED Controlled Resistor" as mention by Phil.
In fact I am using VTL5C4.
Thanks for your comments, I will experiment on them and post the results.
For now I intend to test this:
http://home.earthlink.net/~sycochkn1/rtd.pdf
It may be what I needed.
Bye
Jacques
This was one of the solutions suggested.
http://home.earthlink.net/~sycochkn1/rtd2.pdf
Bob
.
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- Correcting a LED response curve?
- From: Jacques St-Pierre
- Re: Correcting a LED response curve?
- From: Jacques St-Pierre
- Correcting a LED response curve?
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