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Voltage Divider Calculator

Calculate voltage, resistor values, or division ratio for resistor divider networks.

V
Vin = 12VR1VoutR2GND
Output Voltage
Current
0.600 mA
Power R1
3.600 mW
Power R2
3.600 mW

Voltage Divider Formula

Vout = Vin × R2 / (R1 + R2)
The output voltage is a fraction of the input, determined by the resistor ratio.

Common Applications

Level Shifting

Convert 5V logic signals to 3.3V for microcontrollers. Example: R1=10kΩ, R2=20kΩ gives 3.33V output.

ADC Reference

Scale higher voltages to ADC input range. Measure 0-24V with a 3.3V ADC using proper divider ratio.

Battery Monitoring

Divide battery voltage to measurable range. Use high-value resistors to minimize current drain.

Biasing

Set DC operating points for transistor amplifiers. Create stable bias voltages from supply rails.

Potentiometer

Variable voltage divider for volume control, dimming, or adjustable reference voltages.

Feedback Networks

Set gain in op-amp circuits. Determine output voltage ratio in switching regulators.

Design Considerations

Loading Effects

The load impedance affects output voltage. For accurate division, load impedance should be at least 10× greater than R2. Use a buffer amplifier if needed.

Power Dissipation

Choose resistor values high enough to limit current and power dissipation. For battery-powered devices, use 100kΩ+ to minimize drain.

Accuracy

Use 1% tolerance resistors for precision applications. Temperature coefficient affects accuracy in varying conditions.

Frequency Response

Parasitic capacitance limits high-frequency performance. For AC signals, use lower resistor values or add compensation.