I'm measuring input voltages between 2v and 3v (3v volts corresponds to a reading of 0 and 2v corresponds to a reading of 10,000) on the analogue in of my arduino. I would like to measure the voltage at the highest possible resolution of the arduinos A/D converters.Using an operational amplifier and common resistors how would I convert a voltage range of 3V - 2V to a corresponding 0v - 5v for the arduino inputs.
I tried Using the simplified method on this page Scaling Voltages With Op amps
|Gain| = Output Range / (Vin.max â€“ Vin.min) so gain would be 5
Gain = Rg / Rin so Rin = Rg/Gain picking a 10k resistor for Rg i get Rin as 2k
Voff = Vin.max * ( |Gain| / ( |Gain| + 1 )) so 3 * (5/(5+1) - this part confuses me, I would think that the offset is simply 2 because I know that the lowest voltage I need to measure is 2V
Voff = Rbot / (Rtop + Rbot) * Vref
and here is where I get lost