The **S500-63-R** is a high-performance, fast-acting miniature glass tube fuse manufactured by **Eaton (Bussmann Series)**. It is designed to protect delicate electronic circuits from overcurrent conditions. ### Technical Specifications Below are the primary electronic characteristics of the S500-63-R: | Feature | Specification | | :--- | :--- | | **Current Rating** | 63mA (0.063 Amps) | | **Voltage Rating (AC)** | 250 VAC | | **Fuse Type** | Fast-Acting (F) | | **Material** | Glass Tube with Nickel-plated Brass Endcaps | | **Dimensions** | 5mm x 20mm | | **Interrupt Rating** | 35A @ 250VAC | | **Resistance (Cold)** | ~18.5 Ohms | | **RoHS Compliant** | Yes | --- ### Core Electronic Components & Construction 1. **The Element:** Inside the glass tube is a fine wire filament composed of a specific alloy. Because this is a **63mA** fuse, the wire is extremely thin. It is designed to melt almost instantly when the current exceeds the 63mA threshold to prevent damage to downstream components. 2. **The Housing (Glass):** The transparent glass body allows for easy visual inspection. If the fuse has blown due to a short circuit, you will often see a dark smudge or a broken wire inside. 3. **Endcaps:** The "R" in the part number signifies it is **RoHS compliant**. The endcaps are made of conductive metal (usually brass with nickel plating) to ensure a low-resistance connection to the fuse holder or clips. ### Application Use Cases This specific fuse is used in low-power electronic applications where precision is required: * **Power Supplies:** Protecting the primary side of small transformers. * **Test Equipment:** Multimeters and oscilloscopes often use 5x20mm fuses for input protection. * **Control Boards:** Industrial PLCs or sensitive PCB assemblies where a small surge could destroy integrated circuits. ### Comparison: Fast-Acting vs. Time-Delay It is critical to note that the S500 series is **Fast-Acting**. * **S500-63-R (Fast):** Breaks the circuit immediately upon detecting a spike. * **S506-63-R (Time-Delay):** Allows for a brief "inrush" current before blowing. * *Warning:* Never replace a Time-Delay fuse with a Fast-Acting one (like the S500) unless specified, as it may blow during normal startup. ---