The **3AG 3.5-R** is a specific model of an electrical fuse. It follows the standard "3AG" physical size but includes specific electrical characteristics denoted by its alphanumeric code. --- ## 1. Technical Specifications The following table summarizes the key physical and electrical properties of the 3AG 3.5-R: | Property | Specification | | :--- | :--- | | **Type** | Glass Body Cartridge Fuse | | **Size (Standard)** | 3AG (also known as 1/4" x 1-1/4" or 6.3mm x 32mm) | | **Current Rating** | 3.5 Amperes | | **Voltage Rating** | Typically 250V AC | | **Speed Characteristic** | Fast-Acting (Normal Blow) | | **Termination** | Cartridge (Ferrule) | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | --- ## 2. Component Breakdown ### A. The "3AG" Prefix This refers to the **size and material**. 3AG stands for "Size 3 American Glass." It is the most common size for older automotive applications and modern industrial/consumer electronics. * **Dimensions:** 6.35 mm (diameter) × 31.75 mm (length). ### B. The "3.5" Value This is the **Current Rating**. The fuse is designed to allow up to 3.5 Amps of current to pass through continuously. If the current exceeds this threshold significantly, the internal element will melt to break the circuit. ### C. The "-R" Suffix In the electronic component industry (particularly with manufacturers like Littelfuse or Bel Fuse), the **-R** stands for **RoHS Compliant**. This means the part is manufactured without hazardous substances like lead, cadmium, or mercury. --- ## 3. Usage and Applications Because this is a **Fast-Acting** fuse, it is used to protect sensitive electronic components that cannot withstand a momentary surge in current. * **Internal Power Supplies:** Used on PCBs to protect against short circuits. * **Consumer Electronics:** Found in older amplifiers, test equipment, and appliances. * **Control Panels:** Used in industrial settings to protect low-current control loops. --- ## 4. Visual Identification * **Body:** Transparent glass tube (allows for visual inspection of a blown filament). * **End Caps:** Nickel-plated brass caps. * **Markings:** The caps are usually stamped with "3.5A 250V" and the manufacturer's logo.