1. What is a 4-Digit SMD Resistor Code Calculator?

Definition: This calculator decodes the resistance value from 4-digit SMD resistor markings.

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

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)
• \( digit3 \) — Third significant digit (0-9)
• \( digit4 \) — Exponent (multiplier power of 10)

Explanation: The first three digits represent the significant figures, and the fourth digit represents the power of ten multiplier.

3. Importance of SMD Resistor Codes

Details: Surface Mount Device (SMD) resistors use numeric codes because their small size makes color coding impractical. Proper decoding ensures correct component selection.

4. Using the Calculator

Tips: Enter each digit of the 4-digit code. The exponent (fourth digit) can range from -2 to 9, representing multipliers from 0.01 to 1,000,000,000.

5. Frequently Asked Questions (FAQ)

Q1: What does "4702" on a resistor mean?
A: 470 × 10² = 47,000 Ω or 47 kΩ (digits 4,7,0 with multiplier 2)

Q2: How is this different from 3-digit codes?
A: 3-digit codes have two significant digits and one multiplier digit, while 4-digit codes provide higher precision with three significant digits.

Q3: What about resistors marked with "R"?
A: "R" indicates a decimal point (e.g., "4R7" = 4.7 Ω). This calculator is for numeric codes only.

Q4: Can the exponent be negative?
A: Yes, negative exponents represent values below 1 ohm (e.g., exponent -2 means ×0.01).

Q5: How accurate are these resistor values?
A: The code shows nominal value only. Actual tolerance is not indicated in the 4-digit code.