Impedance of a DC voltage divider.

If I remember right

R or (Z) = (R1*R2) / (R1+R2)

Using the 3 to 1 example with 10K resistors - Z = 6.6K
Using the 4 to 1 example with 10K resistors - Z = 7.5K

No problem here, Besides that, I use the 3 to 1 example, It does work.

Asbestos <> RoHS Compliance