Calculate voltage division in resistor circuits. Find output voltage, resistor values, current flow, and power dissipation.
Circuit Diagram
Vin (+)
│
[R1]
│
├──── Vout
│
[R2]
│
GND (-)
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A voltage divider is one of the most fundamental circuits in electronics. This calculator helps you determine output voltage, find required resistor values, and analyze current and power characteristics.
A voltage divider uses two resistors in series to produce an output voltage that is a fraction of the input voltage. The output is taken from the junction between the resistors. This simple circuit is used in sensor interfaces, reference voltages, and signal conditioning.
Voltage Divider Formula
V_{out} = V_{in} × R₂ / (R₁ + R₂)Calculate Vout, R1, or R2 based on your known values.
Get current flow and power dissipation for each resistor.
See the circuit configuration and understand component placement.
Scale sensor signals to match ADC input ranges.
Create stable reference voltages for comparators.
Interface between different voltage logic levels.
Understand how variable resistors affect voltage.
Yes! An unloaded voltage divider provides the calculated voltage. Adding a load draws current and reduces the output. For light loads, use lower resistance values or add a buffer amplifier.
Start with the ratio needed for your voltage division, then consider power dissipation and load effects. Higher resistances waste less power but are more sensitive to loading.
The basic formula works for AC with pure resistors. For capacitors or inductors, you need to account for impedance which varies with frequency.
For precision voltage references, use 1% or better tolerance resistors. For general applications, 5% is usually acceptable. Consider temperature coefficients for critical applications.