The **5HFP315-R** is a specific type of electronic component known as a **Subminiature Radial Lead Fast-Acting Fuse**. It is part of the 5HFP series manufactured by companies like Bel Fuse Inc. These components are critical for protecting sensitive electronic circuits from overcurrent conditions. --- ### 1. Key Technical Specifications The part number "5HFP315-R" can be broken down to understand its characteristics: | Feature | Specification | |:---|:---| | **Fuse Type** | Fast-Acting (Quick Acting) | | **Current Rating** | 315mA (0.315 Amperes) | | **Voltage Rating (AC)** | 250V AC | | **Package / Case** | Radial Lead (Micro Fuse), Round Body | | **Mounting Type** | Through-Hole | | **Termination** | Radial (Two pins protruding from the bottom) | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | --- ### 2. Physical Characteristics The 5HFP series is designed for space-saving on Printed Circuit Boards (PCBs). * **Form Factor:** It features a small, cylindrical plastic body. * **Dimensions:** Typically ~8.5mm in diameter and ~8mm in height. * **Lead Spacing:** Usually 5.08mm between the two pins. * **Durability:** The plastic casing is often thermoplastic and UL 94-V0 flammability rated. --- ### 3. Functional Behavior As a **Fast-Acting** fuse, the 5HFP315-R is designed to open (blow) very quickly when the current exceeds 315mA. * **Fast-Acting vs. Time-Delay:** Unlike "Slow-Blow" fuses, this fuse does not tolerate temporary current surges (like motor startups). It is used for circuits where even a brief spike could damage delicate semiconductors. * **Interrupting Rating:** It is capable of safely breaking the circuit at specific fault current levels (often 35A or 50A depending on the specific voltage environment). --- ### 4. Common Applications Due to its small size and fast response time, you will commonly find this part in: * **Power Supplies:** Protecting the primary or secondary stages of AC/DC adapters. * **Consumer Electronics:** Chargers, LED lighting drivers, and televisions. * **Industrial Equipment:** Control boards and instrumentation where space is limited. * **Battery Chargers:** Preventing overcurrent during the charging cycle. --- ### 5. Identification Code If you are looking at the component, the markings usually follow this logic: ```text 5HFP 315mA 250V (Safety Logos: UL, VDE, etc.) ```