## Electronic Specifications: 3AG12-R The **3AG12-R** is a specific model of a **fast-acting glass tube fuse**. The "3AG" designation refers to the physical size standard (also known as 0AG or 1/4" x 1-1/4"), and the "-R" suffix typically indicates compliance with **RoHS** (Restriction of Hazardous Substances) standards. --- ### Technical Specifications | Parameter | Specification | | :--- | :--- | | **Part Number** | 3AG12-R | | **Current Rating** | 12 Amperes | | **Voltage Rating** | 250 Volts AC | | **Fuse Type** | Fast-Acting / Fast Blow (F) | | **Body Material** | Glass Tube | | **Termination Style** | Cartridge (Ferrule) | | **Standard Dimensions** | 6.35mm x 31.75mm (1/4" x 1-1/4") | | **RoHS Compliant** | Yes | --- ### Key Features and Construction 1. **Fast-Acting Response**: Designed to open (blow) quickly when the current exceeds the 12A rating. Unlike "Slow-Blow" (Time-Delay) fuses, these do not have a built-in delay to handle temporary surges. 2. **Glass Body**: The transparent glass allows for easy visual inspection. If the internal wire is broken or the glass is blackened, the fuse is blown. 3. **Physical Standard**: The **3AG** size is one of the most common fuse sizes used in North America, particularly in older consumer electronics, automotive testers, and power supplies. 4. **Nickel-Plated Brass Caps**: The end caps provide high conductivity and corrosion resistance for secure contact within a fuse holder or clip. --- ### Typical Applications * **Power Supplies**: Protecting the primary side of AC/DC converters. * **Consumer Electronics**: Used in amplifiers, older television sets, and appliances. * **Industrial Equipment**: General circuit protection where high inrush currents are not expected. * **Test Instruments**: Multimeters and diagnostic tools often use this size for overload protection. --- ### Safety Warnings * **Replacement**: Always replace a 3AG12-R with a fuse of the same current (12A) and voltage (250V) rating. * **Voltage**: You can use a 250V fuse in a 125V circuit, but you **cannot** use a lower voltage fuse in a higher voltage circuit.