AVR-Chat

Hello James,

Some suggestions:
Choose a voltage reference implementation with minimal noise, since now
100uV noise becomes 1bit of the result, and simple voltage
references/regulators surely have more noise than that. Make use of RC
filtering on reference voltage. if you use simple resistor divider, do
not take too high resistor values, since thermal noise in a resistor is
proportional to square root of resistance value.

Don't forget to inform us about the results.. :)

Regards

Murat Karadeniz
http://www.onlinefavbar.com/mukas


-----Original Message-----
From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On
Behalf Of James Washer
Sent: Sunday, November 27, 2005 10:16 PM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Question on using AVR (Mega8) ADC for low voltage
measurements


I need to measure voltages in the 0-50mV range. I suspect the answer
here is to use an amp to get this to a more reasonable level (say
0-2.5V) however I was wondering if it is ok to just supply AREF to 0.1
volts.. I suspect this is a bad idea, but I wanted to know for sure.

thanks

 - jim



 
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