Voltage Divider Calculator
Calculate output voltage for a resistor voltage divider.
V_out
2.5000 V
R₂
10.000 kΩ Ω
Ratio (R2/R1+R2)
50.00%
Design resistor voltage dividers instantly
Calculate the output voltage or find the resistor values needed for a specific ratio. The circuit diagram updates live as you type.
Frequently asked questions
- What is a voltage divider?
- A voltage divider is two resistors (R1 and R2) in series, where the output is taken at the junction. Vout = Vin × R2 / (R1 + R2).
- When should I use a voltage divider?
- Voltage dividers are used to scale down voltages, for level shifting (e.g., 5V to 3.3V), biasing transistors, and creating reference voltages. They are not suitable for powering loads with significant current draw.
- What is the loading effect?
- When a load is connected to the output of a voltage divider, it appears in parallel with R2 and lowers the effective resistance, changing Vout. Use a buffer (op-amp follower) to avoid this.
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