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Electrical Fundamentals

Voltage Divider Calculator

Voltage Divider converts the entered electrical measurements into output voltage. Use it to find the unloaded voltage-divider output.

Enter values for output voltage

Use one consistent electrical operating case for all fields.

V

Enter source voltage in V.

Ω

Enter upper resistance in Ω.

Ω

Enter lower resistance in Ω.

How Voltage Divider works

The example applies Vout = Vin × Rbottom ÷ (Rtop + Rbottom). Voltage Divider uses Source voltage, Upper resistance, Lower resistance to report Output voltage.

With the loaded values, output voltage evaluates to 3.84 V. Hold the remaining entries steady while testing an uncertain input.

Inputs for Voltage Divider

Source voltage, Upper resistance, and Lower resistance belong to Voltage Divider. Keep source units with source voltage.

Use the defaults to understand the output, then enter the real circuit or energy data.

Source voltage
Example entry: 12 V.
Upper resistance
Example entry: 10000 Ω.
Lower resistance
Example entry: 4700 Ω.

Reading the Voltage Divider result

This output represents Voltage Divider. Electrons transferred belongs in the separate Electron Flow worksheet.

Compare the output with equipment limits and the applicable design margins.

Measurement and units

Use measured values and keep prefixes such as milli, kilo, and mega consistent before calculating. Check prefixes on source voltage.

Alternatives should share one documented measurement convention. For equivalent resistance, use Parallel Resistance Calculator.

Limits of this calculation

A connected load changes the lower branch resistance and therefore the output.

Unlisted circuit behavior remains outside the computed result. Unentered effects remain outside Voltage Divider.

Questions about Voltage Divider

What does Voltage Divider calculate?

Voltage Divider reports output voltage.

Can Source voltage be zero?

For Voltage Divider, measure any zero source voltage directly.

Why can output voltage differ from measurement?

A connected load changes the lower branch resistance and therefore the output. Recheck source voltage.

Should the result be rounded?

Keep extra digits while comparing cases, then round to the precision supported by source voltage.