Sry for my english im french :3
Trying to use the example of the Adafruit INA219B library to get the voltage and the current of an LCD.
The problem is that when there was no display on the LCD i get this values (maybe it is in standby) :
When there is a display i get this values :
I dont understand why the voltage drops significantly if you can explain to me it could be so kind ;D
Are you using the Adafruit board.
If so, how did you connect it to the Arduino.
Leo..
Ah yes didnt said it my bad ^^ just go see it on this link :
Maybe it is false i dont know i made it from the datasheet page 9 : Download - Parallax
RaionD:
Maybe it is false i dont know i made it from the datasheet
Still don't know if you have a factory-made board, or you are using the bare chip with supporting parts.
You could post a picture of the setup.
Leo..
Well i'am using an Arduino Uno card just bought on this website with a simple breadboard as you can see in the picture :
Ir seems everything is connected right.
Not sure what the cause is.
Try some other load on the curent sensor instead of the LCD.
e.g. a LED/resistor.
Leo..
The problem is that i cant test cause the materials are at my high school... I know it's delicate but you really have 0 idea ? 
Please man i really need your help 
i have to explain it tomorrow or juste make a theory ...
I don't have a crystal ball.
All I can see is that the wiring seems to be ok.
You just have to try things untill you see a change.
Sometimes things are unexplainable untill you start prodding.
How often are those wires used at school.
Maybe there is a wire broken on the inside.
I suggested using another load than the LCD to see if that fixed it. Did it?
The INA doesn't work below ~3volt.
Did you measure voltages with a DMM in the fault state?
Leo..
Okay I get it I will start prodding !
I will try with a led or something else and change wires
I don't even know what is a DMM just stop waste time for me it's useless go help other people 
Really thank you for your help see you man you are a nice guy !
RaionD:
Please man i really need your help
Scientific method: Make a theory that can be tested. Test, prove/disprove, make new theory, test... repeat.
Okay so re i bought the starter kit arduino then i can make tests at my home ! I made a test with a LED and i get this values :
You have in comment of the link the color of the LED and the value of the resitor.
The values seems logic for me so i don't understand the problem with the LCD ^^
Anyway i have to measure the current values from a solar panel so it's not that serious