I tried to measure voltage with INA219A connected to Arduino. As datasheet says INA219 works from 3V to 5.5V supply voltage but I get different values for bus voltage when I change supply voltage. Here are some values I get, when I measure Arduino's 5V output (which is actually 4.6V):
- At 3V supply I get 4.54V,
- At 3.5V --> 3.34V,
- At 4V --> 2.93V,
- At 4.6V --> 2.48V.
I've measured bus voltage myself as voltage between GND and Vin- as mentioned in datasheet and get 4.6V regardless supply voltage.
All was connected like in the picture below:
I tried to supply INA219 from batteries and measure Arduino's 5V. When I supply 3V I get nearly 4.6V what the multimeter shows but when I supply 4.5 V I get 2.5V. The same question remains regardless INA219 is powered from batteries or potentiometer.