The part number **3AG 3A P 3.5-R** refers to a specific type of electronic fuse manufactured by **Bel Fuse Inc.** This is a glass-bodied, fast-acting fuse commonly used in power supplies, monitors, and consumer electronics. Below is a detailed breakdown of the technical specifications and the meaning of each segment in the part number. --- ### Part Number Breakdown | Segment | Meaning | Description | | :--- | :--- | :--- | | **3AG** | Case Style | Standard size: 6.3mm x 32mm (1/4" x 1-1/4"). | | **3A** | Current Rating | Rated for a continuous current of **3 Amperes**. | | **P** | Mounting Style | Pigtail Leads (Axial Leads) for through-hole PCB mounting. | | **3.5** | Length | 3.5mm lead length (standard for this series). | | **-R** | Compliance | RoHS compliant (Lead-free). | --- ### Technical Specifications | Feature | Specification | | :--- | :--- | | **Fuse Type** | Cartridge, Glass Body | | **Response Time** | Fast Acting (F) | | **Voltage Rating (AC)** | 250V | | **Interrupting Rating** | 100A @ 250V AC / 10,000A @ 125V AC | | **Dimensions** | 6.35 mm Diameter x 31.75 mm Length | | **Termination** | Axial (Through-hole) | | **Operating Temp** | -55°C to +125°C | --- ### Key Features and Applications #### 1. Fast-Acting Mechanism Unlike "Slow-Blow" fuses, this part is designed to open almost instantly when an overcurrent occurs. This is critical for protecting sensitive semiconductor components that cannot withstand even short-duration surges. #### 2. Axial Pigtail Leads The "P" in the part number signifies that the fuse has wire leads attached to the end caps. This allows the fuse to be soldered directly onto a Printed Circuit Board (PCB) without requiring a separate fuse holder. #### 3. Typical Applications * **Power Supplies:** Primary protection on the AC input side. * **Industrial Equipment:** Protecting control circuits. * **Consumer Electronics:** Used in older CRT monitors, audio amplifiers, and power adapters. --- ### Comparison: Standard vs. Pigtail The 3AG series is available in two main physical formats: 1. **Standard:** Just the glass tube (requires a fuse clip or holder). 2. **Pigtail (3AG P):** Includes the leads for direct soldering (this specific part).