Hi Im very new to electronics and had a pretty basic question about voltage reference.
So Ive finally understood that in order to check a voltage in most circuits, a voltage reference is used. The way i visualize this is a chip having 5 wires; the first 2 go to the battery which the voltage needs to be measured, another 2 go to a steady power source(the voltage from the first battery gets compared to this steady source and a voltage reading is obtained) and the last wire is an analog wire(ex. to use on arduino for displaying the voltage read).
I know that if i use only 1 battery for both the voltage readings and to power the voltage reference chip, i will always get a value of 1023, because the voltage measured is always compared to that same value giving a max voltage all the time.
With this in mind my question is: How do i use only 1 power source(in this case the battery, without the steady power source) to power the whole circuit and read the voltage of that same battery? Im basically asking how for example phones are able to measure their battery voltage even without a mini battery powering the voltage reference circuit. Thanks in advance.