The part number **4W13-R** typically refers to a specific type of **high-wattage wirewound resistor**, often manufactured by companies like Ohmite or as part of a generic industrial component series. Below is a detailed breakdown of the electronic specifications and characteristics associated with this part. --- ### 1. General Specifications The "4W" prefix usually indicates the physical size and power rating, while the "R" indicates the resistance value. | Parameter | Specification (Typical) | | :--- | :--- | | **Component Type** | Fixed Resistor | | **Technology** | Wirewound (Ceramic Core) | | **Power Rating** | 4 Watts to 13 Watts (Series dependent) | | **Tolerance** | ±5% (Standard) | | **Coating** | Vitreous Enamel or Silicone Ceramic | | **Mounting Type** | Through-Hole (Axial Leads) | --- ### 2. Breakdown of the Part Code While naming conventions vary slightly by manufacturer, the code usually breaks down as follows: * **4W**: Often refers to the wattage (4 Watts) or a specific physical frame size (Series 40). * **13**: Can represent the physical length (in millimeters) or a specific sub-series. * **R**: Indicates the decimal point for resistance (e.g., 4R7 = 4.7 Ohms). If the "R" is at the end, it often signifies compliance with **RoHS** (Restriction of Hazardous Substances) standards. --- ### 3. Key Characteristics 1. **Heat Dissipation:** Wirewound resistors are designed to handle high temperatures. They use a ceramic core to dissipate heat efficiently. 2. **Durability:** Because they are made of wire wrapped around a core, they are highly resistant to electrical surges and pulses compared to film resistors. 3. **Inductance:** Since they are coils of wire, they have inherent **inductance**. They are not ideal for high-frequency applications unless specified as "non-inductive." 4. **Stability:** They offer excellent long-term stability and a low Temperature Coefficient of Resistance (TCR). --- ### 4. Common Applications Due to its power handling capabilities, the 4W13-R is commonly found in: * **Power Supplies:** Used as a bleeder resistor or for voltage dropping. * **Motor Controllers:** For current sensing or limiting. * **Industrial Equipment:** Heavy-duty circuitry where heat is a factor. * **Audio Equipment:** Used in speaker crossover networks. --- ### 5. Technical Precautions ```cpp // Safety Considerations for 4W13-R Resistors: 1. Surface Temp: Can exceed 200°C; keep away from heat-sensitive parts. 2. Derating: At high ambient temperatures, the 4W rating must be reduced. 3. Spacing: Ensure at least 10mm clearance from the PCB to allow airflow. ``` ---