The **5ST5-R** is a specific part number typically associated with **Slow-Blow (Time-Delay) Glass Tube Fuses**. These are foundational electronic components used to protect circuits from overcurrent conditions. ### 1. General Specifications The "5ST" series usually refers to a standard $5 \times 20\text{ mm}$ miniature fuse, while the "-R" suffix denotes **RoHS compliance** (Restriction of Hazardous Substances). | Feature | Specification | | :--- | :--- | | **Dimensions** | $5\text{ mm} \times 20\text{ mm}$ ($0.2" \times 0.79"$) | | **Fuse Type** | Glass Tube | | **Characteristic** | Time-Delay / Slow-Blow (T) | | **Standard** | IEC 60127-2 Sheet 3 | | **Material** | Glass Body, Nickel-plated Brass Caps | --- ### 2. Key Electrical Characteristics The 5ST5-R series is designed to handle temporary surges (like motor startups or powering on a capacitor) without blowing immediately. * **Time-Delay (Slow-Blow):** Unlike "Fast-Acting" fuses, these contain a thermal element (often a coiled wire or a weighted filament) that allows a brief period of overcurrent. * **Breaking Capacity:** Usually rated for low breaking capacity (e.g., $35\text{A}$ or $10$ times the rated current at $250\text{VAC}$). * **Voltage Rating:** Typically rated up to **250V AC**. --- ### 3. Comparison: Slow-Blow vs. Fast-Acting It is critical not to swap a 5ST (Slow-Blow) with a 5SF (Fast-Acting) fuse in sensitive electronics. | Feature | 5ST (Slow-Blow) | 5SF (Fast-Acting) | | :--- | :--- | :--- | | **Reaction Time** | Delayed (Seconds) | Instantaneous (Milliseconds) | | **Internal Wire** | Often coiled or thick | Thin and straight | | **Application** | Inductive loads (Motors, Transformers) | Resistive loads (LEDs, ICs) | --- ### 4. Common Applications * **Power Supplies:** Protecting the primary side of AC/DC adapters. * **Consumer Electronics:** Televisions, audio amplifiers, and microwave ovens. * **Industrial Equipment:** Small motors and control circuits where "inrush current" is expected. --- ### 5. Part Number Breakdown When ordering or identifying the part, the suffix after the "5" usually indicates the amperage. * **5ST 5-R:** The "5" signifies a **5 Ampere** rating. * **-R:** Indicates the part is Lead-Free and RoHS compliant. ---