Suppose the built in analog to digital converter of a microcontroller has an operating voltage of 0-5 V. These values are converted to integers ranging from 0-1023. So the resolution is 5/1024.
I want to measure an analog value ranging from 0-1 V.
If I multiply the analog value by 5 in a microcontroller that reads the value (using the multiplication operator in software,) will the resolution be 1/1024?
Best Answer
No the resolution will be one-fifth of that at best. 1 volt applied to a 10-bit ADC with 5 volt input full-scale will result in a digital number of 204. That has a resolution of 1 in 204 or 0.49% and will remain at 0.49% even when you multiply up 204 by 5.
Be aware that gain errors and offset errors in the ADC means you can't truly use the full 0 to 5 volt input of an ADC. Maybe 98% of it but not 100%.
Many ADCs can work at a much lower reference voltage and this of course might help you get a better solution.