1. What is a DigiKey SMD Resistor Calculator?

Definition: This calculator decodes the marking on surface-mount resistors to determine their resistance value.

Purpose: It helps engineers, technicians, and hobbyists quickly identify SMD resistor values without memorizing coding systems.

2. How Does the Calculator Work?

The calculator interprets several common coding systems:

• 3-digit code: First two digits are significant figures, third digit is multiplier (e.g., "103" = 10 × 10³ = 10KΩ)
• EIA-96 code: 2-digit number plus letter (e.g., "01C" = 100 × 100 = 10KΩ)
• Letter notation: "R" for decimal point (e.g., "4R7" = 4.7Ω, "R47" = 0.47Ω)
• K/M notation: "K" for kilo, "M" for mega (e.g., "4K7" = 4.7KΩ, "1M5" = 1.5MΩ)

3. Importance of Resistor Code Interpretation

Details: Correctly identifying resistor values is crucial for circuit design, troubleshooting, and repair work.

4. Using the Calculator

Tips: Enter the resistor code exactly as it appears on the component. The calculator will interpret most common coding formats.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between 3-digit and EIA-96 codes?
A: 3-digit codes are simpler but less precise. EIA-96 uses 3 characters (2 digits + letter) for 1% tolerance resistors.

Q2: How do I read tiny SMD resistor codes?
A: Use magnification and good lighting. The smallest components (0402 and smaller) often have no markings.

Q3: What does "R" mean in resistor codes?
A: "R" acts as a decimal point (e.g., "4R7" = 4.7Ω, "R47" = 0.47Ω).

Q4: How accurate are these codes?
A: The code represents nominal value only. Actual resistance depends on tolerance (typically 1% or 5% for SMD resistors).

Q5: What if my resistor has no markings?
A: Very small resistors (0402 or smaller) often have no markings. You'll need to measure them with a multimeter.