Measuring uAmps with INA219 breakout board from Adafruit

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Fadi
 
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Measuring uAmps with INA219 breakout board from Adafruit

Post by Fadi »

Hi forum

I am a little lost in terms of being able to measure micro-amps using the INA219 breakout board from adafruit.
My microamps, I don't mean 0.1 ma resolution, I mean if I have an arduino and is optimized (8Mhz internal oscillator, running at 2.4v...etc etc)
it'll draw perhaps 70uA or 30uA.what ever the number is, that is less than the 0.1ma resolution.

Would it be possible to change the resistor value to change this?

Thanks

F.K.

EDIT: fixed typo.
Last edited by Fadi on Tue Nov 25, 2014 6:44 pm, edited 3 times in total.

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adafruit2
 
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Re: Measuring uAmps with INA210 breakout board from Adafruit

Post by adafruit2 »

you can, but the INA series isn't good for uA measurements, you probably need a 'uCurrent Gold' (google for that)

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Fadi
 
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Re: Measuring uAmps with INA210 breakout board from Adafruit

Post by Fadi »

Thanks for the feedback.

Given that I already have the INA219, can you tell me which resistor to change and what is the value to be able to go down to
uAmp or 10s of uAmp measurements?

(corrected post typo, INA210 should be INA219)

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adafruit_support_mike
 
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Re: Measuring uAmps with INA219 breakout board from Adafruit

Post by adafruit_support_mike »

The INA219's ADC has a maximum range of +/-320mV, so you can use Ohm's Law to find the resistance you need:

V = IR
R = V/I
R = 0.32v / 0.0001A (maximum voltage at 100uA of current)
R = 3200 ohms

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Fadi
 
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Re: Measuring uAmps with INA219 breakout board from Adafruit

Post by Fadi »

Thank you for your input.
(guess i'll be getting a ucurrent gold as soon as they are back in stock)

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