1. What is an SMD Resistor Code 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 without memorizing the coding system.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The first two digits form the significant figures, while the third digit represents the number of zeros to add.

3. Importance of SMD Resistor Codes

Details: SMD resistors are too small for color bands, so they use numerical codes. Understanding these codes is essential for circuit design and repair.

4. Using the Calculator

Tips: Enter the three-digit code components separately. For example, code "472" would be digit1=4, digit2=7, multiplier=2 (resulting in 4700Ω or 4.7kΩ).

5. Frequently Asked Questions (FAQ)

Q1: What about 4-digit SMD codes?
A: For 4-digit codes (E96 series), the first three digits are significant figures and the fourth is the multiplier.

Q2: How do I identify the tolerance?
A: Standard 3-digit codes are typically ±5%. A letter (like J or F) after the digits indicates tolerance.

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

Q4: Are there codes for values below 10Ω?
A: Yes, they use "R" for the decimal place (e.g., "0R5" = 0.5Ω).

Q5: What's the most common mistake when reading codes?
A: Confusing the multiplier digit - remember it's an exponent of 10, not the number of zeros to add.