The term **1556-R** is most commonly associated with industrial electronic components, specifically high-precision resistors or specialized power modules. Below is a breakdown of the primary electronic parts that carry this designation. --- ### 1. High Precision Thin Film Resistors (1556-R Series) In the context of surface-mount technology (SMT), "1556" often refers to the **EIA case size** (though less common than 1206 or 2512) or a specific series from manufacturers like **Vishay** or **Ohmite**. The "-R" suffix typically denotes the **Resistance** value or a **RoHS compliance** rating. | Specification | Typical Value/Description | | :--- | :--- | | **Material** | Thin Film / Metal Film | | **Tolerance** | $\pm 0.01\%$ to $\pm 1\%$ | | **Temperature Coefficient** | 5 ppm/°C to 50 ppm/°C | | **Mounting Type** | Surface Mount (SMD) | ### 2. Specialized Industrial Components The identifier "1556-R" is also found in specific industrial catalog parts: #### A. Power Resistors (Chassis Mount) Certain manufacturers use "1556-R" to identify **Wirewound Resistors** housed in aluminum casings. These are designed for high heat dissipation. * **Application:** Motor braking, load testing, and power supplies. * **Key Feature:** High wattage rating (often 25W to 50W) with a fixed resistance (e.g., 1556-R could imply a 1.5K Ohm resistor in specific coding). #### B. Inductors and Chokes In some power electronics, the code refers to **Toroidal Chokes** or power inductors used for EMI filtering. * **The "R" Suffix:** Usually stands for "Radial" lead configuration or "RoHS Compliant." --- ### 3. Electronic Characteristics Summary If you are looking at a component labeled "1556-R" on a circuit board, it generally follows these parameters: 1. **Resistance/Inductance Value:** The numbers often represent the base value (e.g., 155 x $10^x$). 2. **Environmental Shielding:** Parts with this designation are often "Ruggedized" for industrial environments. 3. **Polarity:** As a resistor or inductor, these parts are non-polarized (can be installed in either direction). --- ### Common Identification Table | Component Type | Likely Function | Identification Tip | | :--- | :--- | :--- | | **Resistor** | Current Limiting | Labeled with "R" and Ohms ($\Omega$) | | **Inductor** | Noise Filtering | Circular/Coiled shape with "R" suffix | | **Connector/Module**| Signal Interface | Multi-pin header labeled 1556-R |