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TOOL IDB-ELE-007
Voltage divider

Desktop only

Engineering tools are available only on desktop screens.

Voltage divider

Two-resistor divider — solve Vout or back-solve R2 from a target Vout. Picks closest E12 standard value.

Schematic Forward
Vin 12 V R1 10 kΩ Vout — R2 3.3 kΩ
Vout vs R2 sweep log R2 scan at fixed R1 + Vin
— V — V 0 100 Ω 10 kΩ 10 MΩ R2 (log) → Vout → R1
Engineering notes

Formula

  • Vout = Vin · R2 / (R1 + R2)
  • R2 = R1 · Vout / (Vin − Vout)

Practical limits

  • Load impedance must be ≫ R1+R2 or the divider sags. Add a follower if loading is heavy.
  • Total resistance trades current draw against noise. 10k–100k for low-power, 1k–10k for noisy.

Result

Live