Can anyone tell me how does ADC works?

[leongch]

how does adc

Hi,
May i knw hw ADC works? what is the usage of the Vref? if 8 bits resolution mean? if i hv an Vref of 2.5V... n d voltage value i would like to measure is 0.5v n 5V ... what will be the digital ouput from the ADC ? thx

 

[seyyah]

ADC converts analog voltage between the vref+ and vref- to digital. vref+ is the max value and vref- is min value. Your signal should be between them. If your Vref- is 2.5V and vref+ is 5V then you can convert signals which are between 2.5 and 5V. The resolution with an 8 bit adc is then (5-2.5)/2^8 =~9.77mV.

This is the simple and general form of the adc. There may be other configurations which accepts negative inputs or gives negative outputs etc.