The **5TT3-R** is a specific series of high-performance, glass-bodied subminiature fuses manufactured by Bel Fuse Inc. These parts are designed for electronic circuits that require reliable overcurrent protection in a compact form factor. ### 1. General Specifications The 5TT3-R series is a **Time-Lag (Slow Blow)** fuse, meaning it is designed to withstand temporary surges in current (such as motor startups or power-on inrushes) without blowing immediately. | Property | Description | | :--- | :--- | | **Material** | Glass Body / Nickel Plated Brass Caps | | **Fuse Type** | 5x20mm Subminiature | | **Response Characteristic** | Time-Lag (T) / Slow Blow | | **Mounting Type** | Holder / Clip / Lead Wire (depending on suffix) | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | --- ### 2. Technical Performance The "5TT" designation refers to the electrical curve and physical size, while the "3" typically denotes the amperage rating in a specific context (though the full part number usually looks like `5TT 3-R` for 3 Amps). #### Electrical Characteristics * **Interrupting Rating:** Usually 100A to 200A at 250V AC. * **Voltage Rating:** Typically rated for 250V AC. * **Resistance to Surge:** Designed to comply with IEC 60127-2 standards. #### Melting Time Limits | Load Percentage | Minimum Time | Maximum Time | | :--- | :--- | :--- | | 150% | 1 Hour | N/A | | 210% | N/A | 2 Minutes | | 400% | 150 ms | 3 Seconds | | 1000% | 20 ms | 300 ms | --- ### 3. Suffix & Variations The exact part number often contains suffixes that determine the physical configuration: 1. **5TT (Base):** The series name. 2. **Amperage:** The number following (e.g., 3 means 3 Amps, 500 means 500mA). 3. **-R:** Indicates "RoHS Compliant" (Lead-Free). 4. **Optional P:** If the part is `5TTP`, it indicates axial pigtail leads are attached for direct soldering to a PCB. --- ### 4. Common Applications Due to the slow-blow nature, these parts are frequently used in: * **Power Supplies:** Handling the initial charging of bulk capacitors. * **Consumer Electronics:** Televisions and audio equipment. * **Industrial Controls:** Small motors or actuators that have inductive kickback. ---