The **3AG125-R** is a specific type of electronic protection component, commonly known as a **glass tube fuse**. It belongs to the "3AG" size standard, which is one of the most widely used formats for cartridge fuses in consumer electronics and industrial equipment. --- ### 1. Technical Specifications The part number typically follows the standards set by manufacturers like Bel Fuse or Littelfuse. Here are the core technical parameters: | Parameter | Specification | | :--- | :--- | | **Type** | Cartridge Glass Fuse | | **Current Rating** | 125mA (0.125 Amps) | | **Voltage Rating** | 250V AC | | **Fuse Speed** | Fast-Acting (F) | | **Dimensions** | 6.3mm x 32mm (1/4" x 1-1/4") | | **Termination Style** | Cartridge (Clip/Holder mount) | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | --- ### 2. Breakdown of the Part Number Understanding the nomenclature helps in identifying equivalent parts: * **3AG:** Refers to the physical size standard. It stands for "Size 3 Automotive Glass," measuring 1/4 inch in diameter and 1-1/4 inches in length. * **125:** Indicates the current threshold. In this context, it represents **125 milliamperes**. * **-R:** Signifies **RoHS Compliance**, meaning the part is manufactured without lead or other hazardous substances restricted by EU environmental standards. --- ### 3. Functional Characteristics * **Fast-Acting Design:** This fuse is designed to blow quickly when an overcurrent occurs. It is ideal for protecting sensitive electronic components that cannot withstand a surge for even a short duration (unlike "Slow-Blow" fuses used for motors). * **Glass Body:** The transparent housing allows for easy visual inspection. If the internal wire is broken or the glass is charred, the fuse is blown and must be replaced. * **Interrupting Rating:** It is designed to safely break the circuit at its rated voltage (250V) without exploding or causing an arc flash. --- ### 4. Common Applications Due to its low amperage and fast response, the 3AG125-R is typically found in: 1. **Power Supplies:** Protecting the input stage of low-wattage devices. 2. **Test Equipment:** Multi-meters and oscilloscopes. 3. **Control Circuits:** Protecting PLCs or sensitive relays in industrial panels. 4. **Audio Gear:** Protecting internal circuitry in amplifiers or mixers. ---