Hello evreryone,
I'm trying to measure the current and the voltage that my 55W Solar Panel produces and read it on my arduino uno. I'm using a voltage divisdor to do so. Although my teacher told us about using amps to help us on reducing the noise and having the right voltage entering on arduino ADC. I've found this circuit on the internet that i'm positive that it is what I need. Although i still can't figure how it works. Shouldn't the amps be connected to the voltage divisor in order to pruduce a gain so that the voltage read on arduino be as close to real as possible?
Thanks a lot everyone. 
You didn't say what the solar panel voltage rating is...
The amplifiers are for set-up for measuring current. Did your teacher tell you to measure current?
It's a little "dangerous" to connect an amplifier with nearly +/- 9V capability to the Arduino, which can be damaged by negative voltage or by voltages above +5V.
A 50/50 voltage divider will protect against voltages greater than +5V but it won't protect it if something "goes wrong" and you get a negative voltage.
You might want to add a [u]protection circuit[/u], or at least add a ~10K resistor in series with the Arduino's input. (There are protection diodes built-into the ATmega chip, but they are low-current. The resistor limits the current so you don't fry the protection diodes.)
Although my teacher told us about using amps to help us on reducing the noise and having the right voltage entering on arduino ADC.
The amplifiers won't reduce noise,* but if the signal is weak they will boost the signal, giving you more usable resolution and a better signal-to-noise ratio if you consider quantization noise.
For voltage measurement, you're using a voltage divider which is an attenuator (the opposite of an amplifier) so it would be silly to use an amplifier.
You can reduce noise with a filter (active or passive) or you can make a digital filter such as with the [u]Smoothing Example[/u].
But, don't assume noise is a problem... Try it first.
I don't know what kind of current you are expecting so I don't know what you can expect out of the amplifiers.
- Any active analog circuit is going to add noise, although the noise from the op-amps may not be significant.
Exactly, at the moment I'm using a RL of 200ohms so that we achieve the greatest power. And yes, our teacher told use to measure current and voltage. So basically as we are using such a low resistor, in order to have decent measures in arduino, we need to put a gain on it right?
Although i have a new doubt how many should the gain be?
And thank you so much I was with pretty messed up ideas.
At the moment we are producing about 6V with a decent lumisosity. The voltage divisor we are using has 20K resistence.
Maybe you should get together with your classmate.
Haha aggree! Thank you for your help!
Have a nice week.