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Electrical Fundamentals

Voltage Divider Calculator

Voltage Divider is a worksheet for comparing one electrical condition at a time, with the result tied to its inputs.

Build the Output voltage case

Small unit changes can move output voltage; confirm scale before using the result.

V

Enter source voltage in V.

Ω

Enter upper resistance in Ω.

Ω

Enter lower resistance in Ω.

The Voltage Divider equation

Vout = Vin × Rbottom ÷ (Rtop + Rbottom)

Only the entries shown on Voltage Divider feed output voltage. If another correction factor matters, keep it in the notes or make a separate run.

Displayed valueDefault case
Output voltage3.84 V
Divider current0.000816 A

Before entering source voltage

On Voltage Divider, confirm decimal placement and unit scale before using output voltage; small prefixes can move an electrical result by orders of magnitude.

  • Source voltage. Example value: 12 V. Enter source voltage in V.
  • Upper resistance. Example value: 10000 Ω. Enter upper resistance in Ω.
  • Lower resistance. Example value: 4700 Ω. Enter lower resistance in Ω.

When source voltage is uncertain, run a low and high case instead of hiding that uncertainty in one entry.

When your notes point to Loaded Voltage Divider, open it after saving this baseline so the two cases do not get mixed.

Detail checks for output voltage

Voltage Divider is simple only after the material, temperature, and measurement condition are known.

When output voltage becomes an input to another worksheet, copy the value only after the units and source condition have been verified.

Use Maximum Power Transfer after saving the Voltage Divider case so the linked result does not overwrite these assumptions.

When the scope changes, move to Ohm's Law and leave this run as the original reference.

Pre-use check for Voltage Divider

  1. Keep the result note attached when copying the answer.
  2. Run a second case for the least certain value.
  3. Review zero or near-zero denominators before trusting a very large answer.
  4. Confirm every unit shown beside the input.
  5. Check whether the value is measured, rated, assumed, or calculated.

Notes to save with Voltage Divider

Keep the unit system, assumed material, and measurement method beside the Voltage Divider result.

Input setSource voltage, Upper resistance, and Lower resistance
ResultOutput voltage
Condition noteA connected load changes the lower branch resistance and therefore the output.

Keep screenshots or notes only when they identify the Voltage Divider source values. A saved final number without entries is hard to audit.

Use Current Divider after saving the Voltage Divider case so the linked result does not overwrite these assumptions.

Common Voltage Divider questions

Why might a real measurement disagree?

A field reading for Voltage Divider can include losses, tolerance, temperature effects, waveform distortion, or instrument limits that the worksheet does not model.