Voltage Divider Calculator - Online Electronics Resistor Tool

A voltage divider is a simple circuit that produces an output voltage (V_out) that is a fraction of its input voltage (V_in). It typically consists of two resistors connected in series. The output is taken from the junction between them.

The output voltage is given by: V_out = V_in × (R₂ / (R₁ + R₂)). This formula comes from Ohm's law. The same current flows through both resistors, and V_out is the voltage drop across R₂.

Voltage dividers are used for level shifting, sensor biasing, reference voltage generation, attenuating signals, and setting gain in amplifier circuits. They are fundamental in analog electronics.

Choose R₁ and R₂ based on the required output ratio and power considerations. Low resistor values draw more current but provide better load regulation. High values save power but are more susceptible to noise and load effects. A good starting point is in the range of 1kΩ to 100kΩ.

Adding a load resistor in parallel with R₂ changes the effective bottom resistance, lowering the output voltage. To minimize this, use a divider with output impedance at least 10 times smaller than the load resistance.

No. Voltage dividers are not designed for power delivery. The current through the divider should be much larger than the load current to maintain stable output. For high current, use a voltage regulator.

Power dissipated on each resistor can be found using P = I²R or P = V²/R. The current I = V_in / (R₁+R₂). Then P_R1 = I² × R₁, P_R2 = I² × R₂. Our tool calculates these automatically.