EASA Module 3 · DC Circuits

The Voltage Divider

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 — V_out = V_in · R2 ÷ (R1 + R2).

Supply voltage 12 V

Wiper position (R2 fraction) 50%

Supply Vin

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Output Vout

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R1 : R2

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Fraction

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V_out 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 V_out down.