The **5MTP1-R** is a specific type of electronic component—specifically a **miniature cartridge fuse**—designed for circuit protection. It is part of the 5MTP series manufactured by **Bel Fuse Inc.** Below is a detailed breakdown of its specifications, construction, and functionality. --- ### 1. Key Technical Specifications The "1-R" in the part number indicates a specific current rating and compliance status. | Parameter | Specification | | :--- | :--- | | **Current Rating** | 1 Ampere (1A) | | **Voltage Rating** | 250V AC | | **Fuse Type** | Glass Body / Miniature Cartridge | | **Speed/Characteristic** | Medium Time-Delay (Slow Blow) | | **Dimensions** | 5mm x 20mm | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | | **Interrupting Rating** | 35A @ 250V AC / 10,000A @ 125V AC | --- ### 2. Physical Construction The 5MTP1-R is built to withstand moderate surges while maintaining a small footprint. * **Body Material:** High-quality glass tube, which allows for easy visual inspection of the internal filament. * **End Caps:** Nickel-plated brass caps for high conductivity and oxidation resistance. * **Internal Element:** A coiled or weighted wire designed to melt only when the current exceeds the limit for a specific duration. * **Terminations:** Axial leads (pigtails) are often present in this series for direct soldering onto PCBs, though the base 5mm x 20mm form factor can also fit into standard fuse holders. --- ### 3. Functional Characteristics #### Medium Time-Delay (Slow Blow) Unlike "Fast-Acting" fuses that blow instantly upon a spike, the 5MTP1-R is designed to handle **Inrush Current**. This is common in devices with motors or large capacitors that draw a brief burst of high power when turned on. The fuse will only "blow" if the overcurrent persists. #### Breaking Capacity It has a "Low Breaking Capacity," meaning it is rated to safely interrupt up to 35 Amps at its maximum voltage of 250V. Using it in a circuit capable of delivering more fault current than this could cause the glass to shatter. --- ### 4. Common Applications The 5MTP1-R is typically found in consumer electronics and industrial equipment: * **Power Supplies:** Protecting the input stage from surges. * **Monitors/Displays:** Safeguarding internal circuitry. * **Medical Devices:** Used in low-power diagnostic tools. * **Chargers:** Providing a safety barrier for battery charging circuits. --- ### 5. Part Number Breakdown Understanding the Bel Fuse nomenclature: * **5MTP:** The series name (5x20mm Medium Time Lag, Pigtail/Axial Lead). * **1:** The amperage rating (1 Amp). * **-R:** RoHS (Restriction of Hazardous Substances) compliant.