The **5TTP 500-R** is a specific type of electronic component known as a **Time-Lag (Slo-Blo) Fuse**. It is manufactured by **Bel Fuse Inc.** and is widely used in power supplies, chargers, and consumer electronics to protect circuits from overcurrent conditions. --- ## 1. Technical Specifications The part number "5TTP 500-R" follows a specific naming convention that identifies its electrical characteristics: | Parameter | Specification | | :--- | :--- | | **Type** | Glass Tube Fuse (Axial Leaded) | | **Current Rating** | 500 mA (0.5A) | | **Voltage Rating (AC)** | 250V AC | | **Characteristic** | Time-Lag (Slow Blow) / T-Type | | **Size/Dimensions** | 5mm x 20mm | | **Termination Style** | Pigtail / Axial Leads (Through-hole) | | **RoHS Status** | Compliant (indicated by the "-R") | --- ## 2. Key Features * **Time-Lag (Slow Blow):** Unlike "Fast Acting" fuses, the 5TTP 500-R is designed to withstand temporary current surges (inrush current) without blowing. This is crucial for devices like motors or power transformers that draw high current for a fraction of a second when turned on. * **Axial Leads:** The "P" in the part number indicates "Pigtail" leads. These are wire leads soldered directly to the end caps, allowing the fuse to be soldered directly onto a Printed Circuit Board (PCB) rather than being placed in a fuse clip. * **Interrupting Rating:** It typically has an interrupting rating of 35A @ 250V AC, meaning it can safely break a short circuit of that magnitude without the glass tube shattering. --- ## 3. Part Number Breakdown Understanding the Bel Fuse nomenclature helps in identifying similar parts: | Segment | Meaning | | :--- | :--- | | **5TTP** | Series Name (5x20mm, Time-Lag, Pigtail Leads) | | **500** | Current Rating (500 Milliamps) | | **-R** | RoHS (Restriction of Hazardous Substances) Compliant | --- ## 4. Typical Applications Because of its slow-blow nature and low current rating, this fuse is commonly found in: 1. **Power Adapters:** Protecting the input stage from internal component failure. 2. **LED Drivers:** Handling the initial surge when the LEDs are powered. 3. **Industrial Controls:** Protecting sensitive control boards that have small inductive loads. 4. **Audio/Video Equipment:** Used in the primary power stage of amplifiers. --- ## 5. Equivalent/Replacement Considerations When replacing this part, ensure the replacement matches: 1. **Amperage:** Must be exactly 500mA. 2. **Voltage:** Can be 250V or higher (never lower). 3. **Speed:** Must be "T" (Time-lag) or "Slow Blow." Replacing it with an "F" (Fast) fuse will cause the fuse to blow immediately upon power-up.