ADC Voltage Divider Calculator

Voltage Divider Formula:

\[ V_{out} = V_{in} \times \frac{R2}{R1 + R2} \]

Output Voltage (V_out):

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1. What is an ADC Voltage Divider Calculator?

Definition: This calculator determines the output voltage of a voltage divider circuit, commonly used in analog-to-digital converter (ADC) applications.

Purpose: It helps electronics engineers and hobbyists design proper voltage scaling circuits for microcontroller ADC inputs.

2. How Does the Voltage Divider Work?

The calculator uses the formula:

\[ V_{out} = V_{in} \times \frac{R2}{R1 + R2} \]

Where:

\( V_{out} \) — Output voltage (volts)
\( V_{in} \) — Input voltage (volts)
\( R1 \) — First resistor (ohms)
\( R2 \) — Second resistor (ohms)

Explanation: The input voltage is divided proportionally based on the ratio of R2 to the total resistance (R1 + R2).

3. Importance of Voltage Dividers

Details: Voltage dividers are essential for scaling down high voltages to safe levels for ADC inputs while maintaining measurement accuracy.

4. Using the Calculator

Tips: Enter the input voltage and both resistor values. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why use a voltage divider with ADCs?
A: Most microcontrollers have ADC reference voltages of 3.3V or 5V, so higher voltages must be scaled down.

Q2: How do I choose resistor values?
A: Select values that create the desired division ratio while keeping current draw reasonable (typically 1kΩ-100kΩ range).

Q3: Does resistor tolerance matter?
A: Yes, for precise measurements use 1% or better tolerance resistors to maintain accuracy.

Q4: What about input impedance?
A: The divider's output impedance (R1||R2) should be much lower than the ADC's input impedance.

Q5: Can I use this for high voltages?
A: Yes, but ensure resistors have proper voltage ratings and consider safety for voltages > 30V.