1. What is an SMD Resistor Calculator?

Definition: This calculator determines the resistance value of surface-mount device (SMD) resistors based on their 3-digit code.

Purpose: It helps electronics hobbyists and engineers quickly decode SMD resistor markings to understand their values.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( R \) — Resistance value (ohms)
• \( digit1 \) — First significant digit (0-9)
• \( digit2 \) — Second significant digit (0-9)
• \( multiplier \) — Power of ten multiplier

Explanation: The first two digits form the significant figures, while the third digit represents the power of ten multiplier.

3. Importance of SMD Resistor Codes

Details: SMD resistors are too small for color bands, so they use numerical codes to indicate their resistance values.

4. Using the Calculator

Tips: Enter the three-digit code from your SMD resistor. The first two digits are the significant figures, and the third is the multiplier.

5. Frequently Asked Questions (FAQ)

Q1: What if my resistor has more than 3 digits?
A: 4-digit codes work similarly, with the first three digits as significant figures and the fourth as multiplier.

Q2: How do I read small SMD resistors?
A: Use a magnifying glass and good lighting. The numbers are typically very small.

Q3: What does "R" mean in SMD codes?
A: "R" represents a decimal point (e.g., 4R7 = 4.7 ohms).

Q4: Are there letter codes for tolerance?
A: Yes, some resistors include a letter after the numbers to indicate tolerance (e.g., "F" = ±1%).

Q5: What's the smallest SMD resistor size?
A: 01005 (0.4mm × 0.2mm) is currently the smallest standard size.