Noise in voltage measurements

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Chris Holt

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Nov 22, 2013, 11:11:36 AM11/22/13
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Does the noise in the voltage measurements improve if you use an external power supply rather than the 5volts from USB?

I am trying to measure a small change in resistance (1ohm to 1.01ohm) that results from the pulsed heating of a fine wire.  If I could reduce the noise just a bit in the measurements the CEE would work for me. 

Thank you for your help! 

Chris

Kevin Mehall

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Nov 24, 2013, 8:45:06 PM11/24/13
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The external power supply mod only provides power for the output amplifier, so it's unlikely to have much effect on the input circuitry, which remains powered from USB.

I do have two suggestions that might help:

Oversample by using a higher sampling rate and a low pass filter in software to remove the noise from the measurements. Pixelpulse does this to some extent if you use a high sample rate and remain zoomed out. If you're trying to compare two scenarios, you could use the API to grab thousands of samples and take the average in each scenario.

Depending on the voltage involved, you might use the gain amplifier to get more resolution in exchange for a lower maximum voltage range. This improves precision, and will reduce discretization noise in the ADC, but won't remove noise from other sources.

--
Kevin Mehall
Nonolith Labs


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