The **GMD-250-R** is a specific model of a time-delay (slow-blow) glass tube fuse manufactured by Eaton (Bussmann Series). It is designed to protect electronic circuits from overcurrent conditions without tripping during temporary power surges. --- ## Technical Specifications | Parameter | Specification | | :--- | :--- | | **Series** | GMD Series | | **Current Rating** | 250mA (0.25 Amps) | | **Voltage Rating (AC)** | 250 VAC | | **Interrupting Rating** | 35A at 250VAC / 10,000A at 125VAC | | **Fuse Type** | Time-Delay / Slow-Blow | | **Body Material** | Glass Tube | | **End Cap Material** | Nickel-plated Brass | | **Dimensions** | 5mm x 20mm | | **RoHS Compliant** | Yes (indicated by the "-R" suffix) | --- ## Key Electronic Characteristics ### 1. Time-Delay Functionality Unlike "Fast-Acting" fuses, the GMD-250-R is engineered to withstand brief surges in current (inrush current). This is crucial for inductive loads like small motors or power supplies where a high initial current is required to start the device. ### 2. The "-R" Suffix In the Eaton/Bussmann catalog, the **-R** suffix stands for **RoHS Compliance**. This indicates that the fuse is manufactured without hazardous substances like lead, making it suitable for modern environmentally regulated electronic assembly. ### 3. Construction Materials * **Glass Body:** Allows for visual inspection to see if the internal filament has melted (blown). * **Filament:** Often designed with a "T-coil" or a weighted element to achieve the time-delay thermal characteristic. --- ## Typical Applications Because of its low current rating (250mA) and time-delay nature, this fuse is commonly found in: * Primary protection for small transformers. * Power supply units for consumer electronics. * Industrial control circuits. * Medical instrumentation.