1. What is an SMT Resistor Code Calculator?

Definition: This calculator determines the resistance value from the 3-digit code found on surface-mount technology (SMT) resistors.

Purpose: It helps electronics engineers, technicians, and hobbyists quickly decode SMT resistor values for circuit design and repair.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( R \) — Resistance value in ohms (Ω)
• \( digit1 \) — First significant digit (0-9)
• \( digit2 \) — Second significant digit (0-9)
• \( multiplier \) — Power of ten multiplier (-2 to 9)

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

3. Importance of SMT Resistor Codes

Details: SMT resistors are marked with a numerical code because their small size makes color bands impractical. Proper decoding is essential for circuit analysis and troubleshooting.

4. Using the Calculator

Tips: Enter the first two digits (0-9) from the resistor code and the multiplier (typically 0-6 for most resistors). The calculator will display the resistance in ohms.

5. Frequently Asked Questions (FAQ)

Q1: What does a code like "103" mean?
A: 103 = (1×10 + 0) × 10³ = 10 × 1000 = 10,000 Ω or 10 kΩ.

Q2: How do I read codes with "R" in them?
A: "R" represents a decimal point. For example, 2R2 = 2.2 Ω.

Q3: What about 4-digit codes?
A: 4-digit codes work similarly but with three significant digits: (digit1×100 + digit2×10 + digit3) × 10^multiplier.

Q4: What's the smallest resistor value this can calculate?
A: With multiplier -2, the smallest is (0×10 + 0) × 10⁻² = 0 Ω. Practical minimum is (1×10 + 0) × 10⁻² = 0.1 Ω.

Q5: How accurate are SMT resistor codes?
A: The code shows nominal value only. Actual tolerance is indicated separately (typically ±1% to ±5%).