Answer to Question #276779 in Physics for jojo

Question

! Suppose that you have a battery with12v, show that a device operating at 4v can be powered by this battery? If estimate the value of resistance that will be used in your proposed cercuit.

Answer 1

We need a voltage divider:

$$R_2=R_1\frac{V_\text{out}}{V_\text{in}-V_\text{out}}=R_1\frac{4}{12-4}=0.5R_1.$$

For $R_1=10\Omega,R_2=5\Omega.$