The **RJS4-R** typically refers to a high-performance **Fuse** manufactured by **Bel Fuse Inc.** This specific part belongs to the RJS series, which is characterized by its radial-lead, miniature design and time-delay (slow-blow) characteristics. --- ### ## Technical Specifications The following table outlines the key electrical and physical properties of the **RJS4-R**: | Parameter | Specification | | :--- | :--- | | **Current Rating** | 4 Amperes (4A) | | **Voltage Rating (AC)** | 600V AC | | **Voltage Rating (DC)** | 250V DC | | **Fuse Type** | Time-Delay / Slow-Blow | | **Mounting Type** | Through-Hole (Radial Lead) | | **Interrupting Rating** | 60A @ 600V AC / 10kA @ 125V AC | | **Material** | Glass Body / Matte Tin-Plated Copper Leads | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | --- ### ## Key Features 1. **Time-Delay Characteristic**: Unlike fast-acting fuses, the RJS4-R is designed to withstand temporary current surges (inrush current) without blowing. This is essential for circuits with motors or capacitors. 2. **High Voltage Rating**: Rated for up to 600V AC, making it suitable for industrial power supplies and ballasts. 3. **Small Form Factor**: The radial lead design allows for a smaller footprint on a Printed Circuit Board (PCB) compared to traditional cartridge fuses. 4. **Board Washable**: The construction is generally robust enough to withstand standard PCB cleaning processes. --- ### ## Common Applications * **Power Supplies**: Protection for the input stage of AC/DC converters. * **Lighting Ballasts**: Often used in electronic ballasts for fluorescent or HID lighting. * **Industrial Controls**: Protection for internal circuitry against overcurrent events. * **Battery Chargers**: Safeguarding the charging circuit from fault conditions. --- ### ## Deciphering the Part Number * **RJS**: Series name (Radial lead, rectangular/cylindrical miniature fuse). * **4**: Current rating (4 Amps). * **-R**: RoHS (Restriction of Hazardous Substances) compliant.