The **55FFD-R** refers to a specific series of **Full-Film Foil Resistors** or **Power Resistors**, often associated with brands like Ohmite or precision component manufacturers. These are designed for high-power applications, current sensing, and industrial electronics. ### 1. Key Technical Specifications Below are the typical parameters for the 55FFD-R series: | Parameter | Specification | | :--- | :--- | | **Component Type** | Full-Film / Metal Foil Resistor | | **Resistance Tolerance** | ±0.1% to ±5% (depending on specific sub-model) | | **Power Rating** | High Wattage (varies by heatsink configuration) | | **Temperature Coefficient** | Low (typically < 50 ppm/°C) | | **Termination Style** | Radial or Screw Terminal | | **Compliance** | RoHS Compliant | --- ### 2. Core Features The "55FFD-R" designation usually implies specific physical and electrical characteristics: * **Foil Technology:** Uses a thin metal foil as the resistive element. This provides superior stability over long periods compared to carbon or wirewound resistors. * **Low Inductance:** Because it is not a wirewound component, it has very low parasitic inductance. This makes it ideal for high-frequency switching power supplies. * **Thermal Management:** Often housed in an aluminum casing or designed to be mounted directly to a heatsink to dissipate heat efficiently. * **Precision:** The "R" suffix often denotes a specific resistance value or a "RoHS" (Lead-Free) certification. --- ### 3. Common Applications These parts are typically found in high-reliability industrial environments: 1. **Current Sensing:** Used in motor control circuits to measure the current flow by monitoring the voltage drop across the resistor. 2. **Braking Resistors:** Used in Variable Frequency Drives (VFDs) to dissipate energy when a motor slows down. 3. **Power Supplies:** Acts as a dummy load or a voltage divider in high-voltage power conversion. 4. **Medical Equipment:** Used where high precision and low drift are required for diagnostic imaging or life-support systems. --- ### 4. Part Number Breakdown (Example) While coding varies by manufacturer, a typical breakdown looks like this: ```text 55 - Series Code (e.g., 55mm spacing or specific frame size) FFD - Full Film Design / Dissipation type -R - Resistance Value or RoHS Compliance indicator ``` ---