1. What is a Resistor Calculator by DigiKey?

Definition: This calculator determines the resistance value of a 3-band resistor based on its color code.

Purpose: It helps electronics engineers, technicians, and hobbyists quickly identify resistor values without manual calculation.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( R \) — Resistance value (ohms)
• \( band1 \) — First significant digit (color band 1)
• \( band2 \) — Second significant digit (color band 2)
• \( band3 \) — Multiplier/exponent (color band 3)

Explanation: The first two bands represent digits, and the third band represents the power of ten multiplier.

3. Importance of Resistor Color Codes

Details: Color coding provides a standardized way to identify resistor values quickly and accurately, especially important for through-hole components.

4. Using the Calculator

Tips: Select the appropriate color for each band from the dropdown menus. The calculator will automatically compute the resistance value.

5. Frequently Asked Questions (FAQ)

Q1: What about 4-band or 5-band resistors?
A: This calculator is for 3-band resistors. Additional bands would represent tolerance and temperature coefficient.

Q2: Why do some multiplier values have negative exponents?
A: Gold and silver bands represent multipliers of 0.1 and 0.01 respectively (10^-1 and 10^-2).

Q3: How accurate are these calculations?
A: The calculation is precise, but actual resistor values have manufacturing tolerances (not accounted for in 3-band resistors).

Q4: What if my resistor has different colors?
A: Ensure you're reading the bands in the correct order (usually starting from the end with the closest band).

Q5: Where can I find more information?
A: Visit DigiKey's technical resources or consult the EIA color code standard.