The EIA 96 code is a marking system used primarily for surface mount device (SMD) resistors with a ±1% tolerance.
The EIA-96 code is a standardized marking system specifically designed for high-precision (±1%) SMD resistors. Due to the small size of these components, a compact yet informative code is necessary.
According to the reference, the EIA-96 SMD resistor code uses three characters (two digits and a letter) in which the digits represent the value (for example, 12 = 12th value of the possible range) and the letter represents the multiplier. The reference also states that the EIA-96 code is used on ±1% tolerance SMD resistors.
This means the code provides two pieces of information:
- The Significant Value: This is indicated by the first two digits. These digits correspond to one of the 96 standard values defined in the E96 series, which is a set of preferred resistor values used for ±1% tolerance components. The number "12" in the example thus refers to the 12th value in this specific series list.
- The Multiplier: This is indicated by the third character, which is a letter. The letter tells you by what power of ten the significant value must be multiplied to get the final resistance value in ohms.
Breaking Down the Code Components
Let's look at how the digits and the letter function:
- Two Digits: These digits range from 01 to 96 and point to the specific three-digit value from the E96 series table. For instance, '12' corresponds to the value '130', '24' corresponds to '178', '48' corresponds to '316', and '96' corresponds to '976'.
- One Letter: This letter acts as the multiplier. Different letters correspond to different powers of ten.
Here's a general idea of how the code works (exact tables for the E96 values and multipliers are extensive, but the structure is key):
Illustrative Example Tables
Example Digit-to-Value Mapping (Based on E96 Series):
| Code Digits | E96 Value |
|---|---|
| 01 | 100 |
| 02 | 102 |
| ... | ... |
| 12 | 130 |
| ... | ... |
| 96 | 976 |
Example Letter-to-Multiplier Mapping:
| Multiplier Letter | Multiplier |
|---|---|
| A | 10⁰ (x1) |
| B | 10¹ (x10) |
| C | 10² (x100) |
| D | 10³ (x1k) |
| E | 10⁴ (x10k) |
| F | 10⁵ (x100k) |
| X or S | 10⁻¹ (x0.1) |
| Y or R | 10⁻² (x0.01) |
| Z | 10⁻³ (x0.001) |
Note: Some letters might have alternative uses or slightly different mappings depending on the manufacturer, but this table shows common practice.
How to Read an EIA-96 Code
To find the resistance value of an SMD resistor marked with the EIA-96 code:
- Look up the first two digits in an E96 series value table to find the significant three-digit value.
- Look up the third letter in a multiplier table to find the multiplier.
- Multiply the significant value by the multiplier to get the final resistance in ohms.
Example: A resistor is marked 12C.
- The digits "12" correspond to the 12th value in the E96 series, which is 130.
- The letter "C" corresponds to a multiplier of 10² (x100).
- Therefore, the resistance value is 130 * 100 = 13,000 ohms, or 13 kΩ.
Another Example: A resistor is marked 48D.
- The digits "48" correspond to the 48th value in the E96 series, which is 316.
- The letter "D" corresponds to a multiplier of 10³ (x1k).
- Therefore, the resistance value is 316 * 1000 = 316,000 ohms, or 316 kΩ.
This compact coding system allows manufacturers to mark high-precision, small SMD resistors clearly while indicating both their precise value (derived from the E96 series) and their magnitude.
