Voltage Divider Calculator - Calculate Output Voltage Easily
Calculator
Use Kobee's Voltage Divider Calculator to find the output voltage of a resistor-based voltage divider circuit
How to Use This Calculator
- Choose to calculate with no load or load
- Enter the input voltage (V𝑖𝑛) and resistor values (Ω, kΩ, or MΩ).
- The calculator will compute the output voltage (V𝑜𝑢𝑡 ).
- Press "Reset" to clear all fields and start a new calculation.
More Calculators
Tips for Using Voltage Dividers
- Ensure your resistor values are appropriate for the desired output voltage.
- Use precision resistors for accurate results in sensitive circuits.
- Avoid drawing too much current from the divider, as it can affect performance.
- For low-power applications, high-value resistors minimize energy loss.
Understanding Voltage Divider Circuits
A voltage divider is a simple yet essential circuit used to split an input voltage into a smaller output voltage. It consists of two resistors connected in series. The voltage is divided across the resistors proportionally to their resistance values. The output voltage is taken from the junction between the two resistors. This circuit is widely used in many electronics applications, such as scaling voltage for sensors or adjusting signals for microcontrollers.
Voltage Divider Formula (No Load)
The output voltage \(V_{out}\) of a voltage divider can be calculated using the following formula:
$$V_{out} = V_{in} \times \frac{R_2}{R_1 + R_2}$$
Where:
- \(V_{in}\) = Input voltage (the voltage supplied to the divider)
- \(R_1\) = The first resistor in the series
- \(R_2\) = The second resistor in the series
- \(V_{out}\) = The output voltage (the voltage across resistor \(R_2\))
Voltage Divider with Load Resistor
When the output voltage is used to power another device or load, the voltage divider’s performance changes. This is because the load resistor \(R_L\) connected to the output creates a parallel resistance with \(R_2\). As a result, the overall resistance at the output is altered, and this affects the output voltage. To account for this, the formula becomes:
$$V_{out} = V_{in} \times \frac{\frac{R_2 \cdot R_L}{R_2 + R_L}}{R_1 + \frac{R_2 \cdot R_L}{R_2 + R_L}}$$
We can simplify this by:
First calculating the equivalent resistance of \(R_2\) and \(R_L\) in parallel:
$$R_{\text{eq}} = \frac{R_2 \cdot R_L}{R_2 + R_L}$$
Then, use the updated voltage divider formula:
$$V_{out} = V_{in} \times \frac{R_{\text{eq}}}{R_1 + R_{\text{eq}}}$$
Working Example
Let’s consider a voltage divider with the following parameters:
- Input voltage (\(V_{in}\)) = 12V
- Resistor \(R_1\) = 1kΩ
- Resistor \(R_2\) = 2kΩ
- Load resistor (\(R_L\)) = 5kΩ
First, calculate the equivalent resistance of \(R_2\) and \(R_L\):
$$R_{\text{eq}} = \frac{2k\Omega \cdot 5k\Omega}{2k\Omega + 5k\Omega} = \frac{10k\Omega^2}{7k\Omega} \approx 1.43k\Omega$$
Now, calculate the output voltage:
$$V_{out} = 12V \times \frac{1.43k\Omega}{1k\Omega + 1.43k\Omega}$$ $$= 12V \times \frac{1.43k\Omega}{2.43k\Omega} \approx 7.06V$$
So the output voltage with the load resistor is approximately \(7.06V\), which is lower than the voltage calculated without a load because the load resistor decreases the effective resistance at the output.
Common Applications of Voltage Dividers
Voltage dividers are widely used in electronics. Some common applications include:
- ⚡ Signal Conditioning: Scaling down voltages for microcontrollers and ADCs.
- 🔋 Battery Level Monitoring: Sensing voltage levels in power systems.
- 📡 Sensor Circuits: Adjusting sensor outputs to match input requirements.
- 🛠 Reference Voltage Creation: Providing a stable reference for other circuits.
Hey there! Thanks for stopping by
We hope you found what you were looking for and were able to step away knowing just that little bit more
Founded by a group of electrical engineers, Kobee's main goal is to simplify electronics design and home automation and making it accesible to everyone, not just the engineering community. In many of our own personal maker journeys we were able to benefit from the amazing open source and community driven content generated by savvy makers all over the world. Though, the issue we always found is that although the content was readily available, the documentation and explanation was sometimes barebones and better suited to the experts that designed it in the first place. We're looking to change that! To explain it as simply and as clearly as we can and to pay it forward to the open source community that we all love
So what can you expect from us? Its unlikely you'll find an in depth explanation of laplace transform here and we're probably not going to delve into the world of imaginary numbers (Sorry). But, if you're looking for straight forward, to the point and simple to understands tutorials, explanations and project examples; we think we just might have you covered.
Our community is at the heart of what we do, so if you have any comments or questions leave them in the comments down below or use the Contact Us Form to get in touch. We'll do our best to help each and every one of you
