/diy/ - Do It Yourself

>>2410904
>i just don't get how that works.

pretty obvious when you look at the formula.
it's the ratio that matters, not the actual values.
100K and 220K gives same answer as 10 ohms and 22 ohms.

>is there any guideline

of course. you want the load resistance to NOT affect the calculation.
by making the dividing resistors 10x smaller than the load, you limit the error to 10%