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if I want a battery monitoring circuit, could I just hook up a wire from 5 V reg into the analog port of the controller?
Quoteif I want a battery monitoring circuit, could I just hook up a wire from 5 V reg into the analog port of the controller?This won't work, since your ADC will max out at the voltage your mcu is powered at. What will happen, with that setup, is that it will always say your battery is full.
so what does the second resistor do if the first one creates heat?
why connecting a resistor between positive and ground doesnt count as a short circuit.
Why 100K, why not higher? the original equation provides 200 K.
The reason why its such a high resistance is to minimize the shorted current to be near zero, while voltage still remains the same. Its shorted, but to where only 5V/100k = .00005A current is wasted. Almost nothing! But it can't be too low, as the ADC requires some current to work (check the datasheets).