1. What is a Voltage Divider Calculator (Reverse)?

Definition: This calculator determines the required R1 resistor value in a voltage divider circuit to achieve a desired output voltage.

Purpose: It helps electronics engineers and hobbyists design voltage divider circuits when the output voltage needs to be set precisely.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( R1 \) — Resistor 1 value (ohms)
• \( R2 \) — Resistor 2 value (ohms)
• \( V_{in} \) — Input voltage (volts)
• \( V_{out} \) — Desired output voltage (volts)

Explanation: The formula rearranges the standard voltage divider equation to solve for R1 when other parameters are known.

3. Importance of Voltage Divider Design

Details: Proper voltage divider calculation ensures accurate voltage levels for sensors, reference voltages, and signal conditioning circuits.

4. Using the Calculator

Tips: Enter R2 value in ohms, input voltage (Vin), and desired output voltage (Vout). Vout must be less than Vin. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is this called "reverse" calculator?
A: Because it calculates R1 (typically the unknown) when other parameters are known, unlike standard calculators that find Vout.

Q2: What are typical applications of voltage dividers?
A: Level shifting, sensor interfacing, reference voltage generation, and signal attenuation.

Q3: What if my calculated R1 isn't a standard resistor value?
A: Use the nearest standard value or combine resistors in series/parallel to achieve the desired value.

Q4: How does load resistance affect the calculation?
A: This calculator assumes no load. For loaded dividers, the parallel combination of R2 and load affects the output.

Q5: What's the maximum current through the divider?
A: I = Vin/(R1+R2). Ensure resistors can handle this power (P = I²R).