# SMD Resistor Code Chart and Identification Guide
## Introduction to SMD Resistors
Surface Mount Device (SMD) resistors are widely used in modern electronics due to their compact size and excellent performance. Unlike through-hole resistors, SMD resistors don’t have color bands but instead use numerical codes to indicate their resistance values. Understanding these codes is essential for anyone working with electronic circuits.
## Understanding SMD Resistor Markings
SMD resistors typically use one of three coding systems:
– Three-digit code: Used for resistors with 5% tolerance
– Four-digit code: Used for resistors with 1% tolerance
– EIA-96 code: A more compact system combining numbers and letters
### Three-Digit Code System
The three-digit system is the simplest and most common. The first two digits represent significant figures, while the third digit indicates the multiplier (number of zeros to add).
Example:
Keyword: SMD Resistor Code
103 = 10 × 10³ = 10,000Ω or 10kΩ
472 = 47 × 10² = 4,700Ω or 4.7kΩ
### Four-Digit Code System
For more precise resistors (1% tolerance), manufacturers use a four-digit code where the first three digits are significant figures and the fourth is the multiplier.
Example:
4702 = 470 × 10² = 47,000Ω or 47kΩ
1001 = 100 × 10¹ = 1,000Ω or 1kΩ
### EIA-96 Coding System
The EIA-96 system uses three characters: two numbers and one letter. The numbers represent a code from a lookup table (01-96), while the letter indicates the multiplier.
Resistance Value Codes (first two digits):
01 = 100 13 = 133 25 = 178 37 = 237 49 = 316 61 = 422 73 = 562 85 = 750 97 = 976
02 = 102 14 = 137 26 = 182 38 = 243 50 = 324 62 = 432 74 = 576 86 = 768 98 = 1.00k
… (and so on up to 96)
Multiplier Letters:
A = 10⁰ B = 10¹ C = 10² D = 10³ E = 10⁴ F = 10⁵ G = 10⁶ H = 10⁷ X = 10⁻¹ Y = 10⁻² Z = 10⁻³
Example:
01C = 100 × 10² = 10,000Ω or 10kΩ
49E = 316 × 10⁴ = 3,160,000Ω or 3.16MΩ
## SMD Resistor Size Chart
SMD resistors come in standard sizes designated by codes:
Code | Length (mm) | Width (mm) | Height (mm) | Power Rating
0201 | 0.6 | 0.3 | 0.23 | 1/20W
0402 | 1.0 | 0.5 | 0.35 | 1/16W
0603 | 1.6 | 0.8 | 0.45 | 1/10W
0805 | 2.0 | 1.2 | 0.45 | 1/8W
1206 | 3.2 | 1.6 | 0.55 | 1/4W
1210 | 3.2 | 2.5 | 0.55 | 1/2W
2010 | 5.0 | 2.5 | 0.55 | 3/4W
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