The **5MT125-R** is a specific type of electronic component, primarily known as a **Subminiature Glass Body Cartridge Fuse**. It belongs to the 5MT series, which is characterized by its "Medium Time-Delay" (slow-blow) characteristics. Below is a detailed breakdown of its electronic specifications and physical properties. --- ### 1. Technical Specifications The "125" in the part number indicates the current rating (125mA), and the "R" typically signifies RoHS compliance. | Feature | Specification | | :--- | :--- | | **Current Rating** | 125 mA | | **Voltage Rating (AC)** | 250V AC | | **Fuse Type** | Glass Body / Cartridge | | **Characteristic** | Medium Time-Delay (Slow Blow) | | **Size / Dimension** | 5mm x 20mm | | **Breaking Capacity** | 35A @ 250V AC / 10K A @ 125V AC | | **Resistance** | Approx. 4.8 Ohms (Cold) | | **RoHS Status** | Compliant (Lead-Free) | --- ### 2. Key Component Features * **Time-Delay Function:** Unlike "Fast-Acting" fuses, the 5MT125-R is designed to withstand temporary surges in current (inrush current) without blowing. This is essential for circuits containing capacitors or small motors that pull more power momentarily upon startup. * **Glass Body Construction:** The transparent glass allows for easy visual inspection to see if the internal filament has melted (blown). * **Brass Caps:** The end caps are typically made of nickel-plated brass to ensure high conductivity and resistance to corrosion. --- ### 3. Common Applications Due to its low amperage and time-delay nature, this fuse is frequently found in: 1. **Consumer Electronics:** Power supplies for small appliances. 2. **LED Lighting:** Protecting drivers from transient spikes. 3. **Industrial Equipment:** Control circuits where small inductive loads are present. 4. **Testing Instruments:** Internal protection for multimeters or signal generators. --- ### 4. Part Number Breakdown Understanding the nomenclature helps in sourcing replacements: | Prefix | Value | Suffix | | :--- | :--- | :--- | | **5MT** | Series Name (5x20mm Medium Time-Lag) | **-R** | | | **125** (Amperage: 125mA) | RoHS Compliant | --- ### 5. Installation Note When replacing a 5MT125-R, always ensure the replacement fuse has the same **voltage rating** (250V) and **time characteristic**. Replacing a "Slow Blow" (T) fuse with a "Fast Acting" (F) fuse of the same amperage will likely result in the fuse blowing immediately upon device startup.