The part number **4-556-R** is typically associated with a specific series of high-precision, thin-film resistor chips or specialized connectors, depending on the manufacturer (most commonly associated with **Ohmite** or **TE Connectivity** components). Below is a detailed breakdown of the electronic specifications and characteristics generally associated with this part series. --- ### 1. General Specifications In most industrial contexts, this part refers to a **Surface Mount (SMD) Resistor** or a specific **Precision Terminal**. Here is a technical overview: | Feature | Specification (Typical) | | :--- | :--- | | **Component Type** | Precision Resistor / Surface Mount Device | | **Resistance Value** | Varies by sub-code (often 556 Ohms if indicated) | | **Tolerance** | ±0.1% to ±1% (High Precision) | | **Power Rating** | 0.1W to 0.25W (Package dependent) | | **Temperature Coefficient** | ±25 ppm/°C to ±100 ppm/°C | | **Operating Temperature** | -55°C to +155°C | --- ### 2. Key Internal Parts & Materials The construction of a "4-556-R" series component involves several layers to ensure stability and conductivity: * **Substrate:** Usually high-purity **Alumina (Al2O3) ceramic**. This provides the base for heat dissipation and mechanical strength. * **Resistive Element:** A thin film of **Nichrome (NiCr)** or a similar metal alloy. This layer is sputtered onto the substrate to achieve precise resistance. * **Protective Coating:** An epoxy or glass overglaze that shields the resistive element from moisture, oxidation, and mechanical abrasion. * **Terminations:** * **Inner Layer:** Silver (Ag) or Copper (Cu). * **Barrier Layer:** Nickel (Ni) to prevent "leaching" during soldering. * **Outer Layer:** Matte Tin (Sn) for RoHS compliance and easy solderability. --- ### 3. Usage and Applications These parts are designed for environments where accuracy is critical. Common applications include: 1. **Medical Instrumentation:** Low-noise circuitry for diagnostic tools. 2. **Telecommunications:** Signal processing and base station power management. 3. **Industrial Controls:** Feedback loops in automated manufacturing systems. 4. **Automotive Electronics:** Sensors and ECU (Engine Control Unit) mapping. --- ### 4. Part Number Decoding (Standard Format) If this is an Ohmite or Vishay style part, the "R" suffix usually denotes **RoHS Compliance** (Lead-Free). ```text 4 - 556 - R | | | | | └── RoHS Compliant (Lead-Free) | └───────── Resistance Value (556 Ohms) └──────────────── Series / Package Size Code ```