The **GMA-5-R** is a specific model of electronic component, primarily known as a **Fast-Acting Glass Tube Fuse**. It is part of the GMA series produced by manufacturers like Eaton (Bussmann) and Bel Fuse. Below is a detailed breakdown of its specifications, construction, and applications. --- ### 1. Technical Specifications The "5" in the part number indicates its current rating, and the "R" typically signifies RoHS compliance. | Feature | Specification | | :--- | :--- | | **Component Type** | Cartridge Fuse | | **Current Rating** | 5 Amperes (5A) | | **Voltage Rating (AC)** | 125V or 250V (Standard dependent) | | **Response Speed** | Fast-Acting / Quick Acting (F) | | **Dimensions** | 5mm x 20mm (Standard Small Dimension) | | **Body Material** | Glass Tube | | **End Cap Material** | Nickel-plated Brass | | **Interrupt Rating** | 200A at 125Vac / 100A at 250Vac | --- ### 2. Physical Construction The GMA-5-R is designed for simplicity and visibility: * **Glass Body:** The transparent cylinder allows for easy visual inspection. If the fuse is "blown," you can usually see a broken wire or dark scorch marks inside. * **Filament:** Inside is a thin metallic wire calibrated to melt when the current exceeds 5 Amps for a specific duration. * **Silver-Plated Caps:** The ends are conductive caps that provide the electrical connection to a fuse holder or clips. --- ### 3. Functional Behavior (Fast-Acting) Unlike "Slow-Blow" (Time-Delay) fuses, the **Fast-Acting** nature of the GMA-5-R means: 1. It reacts almost instantly to current overloads. 2. It is used to protect sensitive electronic components (like ICs and transistors) that cannot withstand even a brief surge. 3. **Note:** It is not suitable for devices with high "inrush" currents (like large motors), as it will blow immediately upon startup. --- ### 4. Common Applications The 5x20mm 5A fuse is widely used in: * **Consumer Electronics:** Power supplies for laptops, monitors, and TVs. * **Small Appliances:** Coffee makers, blenders, and microwave control boards. * **Testing Equipment:** Multimeters and oscilloscopes. * **Industrial:** PLC (Programmable Logic Controller) outputs. --- ### 5. Identification Code Breakdown If you see this printed on the fuse cap, here is what it means: ```text GMA - 5 - R | | | | | └── RoHS Compliant (Lead-Free) | └────── Amperage Rating (5 Amps) └─────────── Series Designation (5x20mm Fast-Acting) ```