## GMD-125-R Fuse Overview The **GMD-125-R** is a specific model of electronic fuse manufactured by Eaton (formerly Bussmann). It belongs to the **GMD Series**, which consists of 5x20mm time-delay glass tube fuses. These are commonly found in consumer electronics, power supplies, and industrial control circuits. ### Technical Specifications | Feature | Specification | | :--- | :--- | | **Current Rating** | 125mA (0.125 Amps) | | **Voltage Rating (AC)** | 250 VAC | | **Fuse Type** | Time-Delay (Slow-Blow) | | **Material** | Glass Tube, Nickel-plated brass endcaps | | **Dimensions** | 5mm x 20mm (Standard Small Dimension) | | **Interrupt Rating** | 35A @ 250Vac | | **RoHS Compliant** | Yes (Indicated by the "-R" suffix) | --- ### Component Breakdown #### 1. Time-Delay (Slow-Blow) Mechanism Unlike "Fast-Acting" fuses, the GMD-125-R is designed to withstand temporary surges in current. This is critical for circuits with inductive loads (like small motors or transformers) that draw a high "inrush" current when first powered on but settle down to a lower operating current. #### 2. The Glass Body The glass construction allows for easy visual inspection. If the fuse has blown due to a minor overload, the internal wire will look snapped. If it has blown due to a major short circuit, the inside of the glass may appear blackened or "smoked." #### 3. The "-R" Suffix In the Eaton/Bussmann catalog, the **-R** stands for **RoHS Compliant**. This means the part is manufactured without the use of lead or other hazardous substances, meeting international environmental standards. --- ### Common Applications The GMD-125-R is typically used for low-power protection in: * **Power Supplies:** Protecting the primary side of small AC-DC adapters. * **Control Circuits:** Used in PLC (Programmable Logic Controller) outputs. * **Audio/Video Equipment:** Protecting sensitive internal circuitry from overcurrent. * **Instrumentation:** Used in multimeters or laboratory equipment. ### Replacement Safety Note ```text WARNING: When replacing a GMD-125-R, never substitute it with a Fast-Acting fuse of the same amperage. A Fast-Acting fuse will likely blow immediately upon startup due to normal inrush currents. Always match the "T" (Time-delay) characteristic. ```