EASA / CAR Part-66 · Module 3 · 3.6 DC Circuits · Cat A · B1/B2
Two resistors in series split the supply voltage in proportion to their values. Move the potentiometer wiper to tap off any fraction of the input, Vout = Vin · R2 ÷ (R1 + R2).
Vout depends only on the ratio of the resistors, not the supply's absolute value. Potentiometers use this to set volume, sensor references and control voltages. Note: connecting a heavy load across the output loads the divider and pulls Vout down.