Voltage Divider Calculator
Calculate output voltage in a voltage divider circuit.
Advertisement
Related Calculators
Ohm's Law Calculator
Calculate voltage, current, resistance, and power using Ohm's Law.
Concrete Calculator
Estimate the amount of concrete needed for a project.
Resistor Color Code Calculator
Determine the resistance value from resistor color bands.
Capacitor Code Calculator
Decode capacitor markings to find capacitance value.
Advertisement
Understanding Voltage Division
A voltage divider is a simple but fundamental series circuit that turns a large voltage into a smaller one. This calculator applies the voltage divider formula to find the output voltage (Vout) across the second resistor (R₂) based on the input voltage (Vin) and the values of the two resistors (R₁ and R₂).
The Voltage Divider Formula Explained
In a series circuit with two resistors, the voltage is divided between them. The output voltage across the second resistor (R₂) is calculated as: Vout = Vin * (R₂ / (R₁ + R₂))
- Vin: The total input voltage applied to the circuit.
- R₁: The resistance of the first resistor.
- R₂: The resistance of the second resistor, across which the output voltage is measured.
How to Use the Calculator
- Input Voltage (V): Enter the total voltage being supplied to the circuit.
- Resistor 1 (R1) (Ohms): Enter the resistance value of the first resistor.
- Resistor 2 (R2) (Ohms): Enter the resistance value of the second resistor.
- Calculate: The tool will display the resulting output voltage (Vout).
Real-World Example
You have a 9V battery and you want to create a reference voltage of approximately 3V. You use two resistors: R₁ = 2000 Ω and R₂ = 1000 Ω.
- Vin: 9V
- R₁: 2000 Ω
- R₂: 1000 Ω
- Calculation:
Vout = 9 * (1000 / (2000 + 1000)) = 9 * (1000 / 3000) = 9 * (1/3) = 3V - The output voltage will be 3V.
Frequently Asked Questions (FAQ)
- What is a voltage divider used for? They are commonly used to create reference voltages, adjust signal levels, and as part of sensor circuits (e.g., with photoresistors or thermistors).
- What is the 'loading effect'? The formula assumes that no current is drawn from the output. If you connect another component to Vout, it will draw current and change the effective resistance of R₂, altering the output voltage. This is known as the loading effect.
- Can I find a resistor value if I know the desired output voltage?
Yes, you can rearrange the formula. For example, if you know Vin, Vout, and have chosen R₁, you can solve for the required R₂:
R₂ = (Vout * R₁) / (Vin - Vout).