Hi there.
I want to build a Low voltage,3 led volt meter that starts measurements at 4.5v and downwards
I have 3 alkaline batteries 1.5v, total of 4.5v that I need to monitor.
I want all the power supply for the circuit drawn from the existing 4.5v that I have (I can not supply it by other batteries or power source due to that space is a matter.)
And when the voltage drops at the lowest value, then again the voltmeter should power it self from the existing pack, lowest voltage that would be
3.10v.
4.5v-3.80v green led,
3.70v-3.40v yellow,
And 3.30v-3.10v red.
Any help would be appreciated.
Thanks.