Vol. IV — Electronics · Tool
Two resistors in series share the supply. The mid-point is a quieter voltage you can use for sensors, LEDs, and reference levels. Change Vin, R1, and R2 — Vout updates as you type.
R1 sits between Vin and the mid-point. R2 sits between the mid-point and ground. Same current flows through both, so the voltage drops in proportion to each resistance: Vout = Vin × R2 / (R1 + R2).
Equal resistors split the supply in half. A larger R2 raises Vout; a larger R1 lowers it. Keep the total resistance high enough that the divider does not waste power, and low enough that whatever you attach to Vout does not pull the mid-point around.
Pick parts on Resistor codes, practice series drops in the Circuit explorer, or size an LED series resistor on LED resistor.