The **HTB-56I-R** is a specific model of an **In-Line Fuse Holder** manufactured by Eaton (formerly Bussmann). It is designed to be mounted on a panel to hold and protect subminiature or standard fuses, acting as a critical safety component in electronic circuits. --- ## 1. Technical Specifications Below are the primary electronic and physical characteristics of the HTB-56I-R: | Feature | Specification | | :--- | :--- | | **Current Rating** | 20 Amperes (UL), 16 Amperes (VDE) | | **Voltage Rating** | 250 Volts AC | | **Fuse Compatibility** | 5mm x 20mm (Metric) | | **Body Material** | High-temperature Thermoplastic | | **Terminal Type** | 3/16" Quick Connect / Solder Terminals | | **Mounting Style** | Rear Hex Nut (Panel Mount) | | **Knob Type** | In-line / Low Profile (Screwdriver slot) | --- ## 2. Key Electronic Components & Functions ### A. The Housing (Body) The body is made from high-grade thermoplastic with a high UL flammability rating. Its electronic purpose is **galvanic isolation**—ensuring that the high-voltage current passing through the fuse does not arc to the metal chassis of the device. ### B. Terminal Contacts The HTB-56I-R features two metal terminals: * **Conductivity:** Made from brass or copper alloy, typically tin-plated to prevent oxidation and ensure low contact resistance. * **Rear Terminal:** Usually connected to the "Line" or "Hot" side of the AC power. * **Side Terminal:** Usually connected to the "Load" side. ### C. The Knob (Carrier) The "I" in the part number refers to the **In-line/International** 5x20mm fuse carrier. * It utilizes a bayonet-style spring-loaded mechanism. * The internal spring ensures constant mechanical pressure on the fuse, which is vital for maintaining a low-resistance electrical path. --- ## 3. Circuit Protection Role The HTB-56I-R acts as the interface between the power source and the sensitive internal electronics. 1. **Overcurrent Protection:** It holds the fuse link that melts during a short circuit. 2. **Ease of Maintenance:** It allows the end-user to replace a blown fuse from the outside of the equipment without opening the main enclosure, reducing the risk of electric shock. 3. **Heat Dissipation:** The design is engineered to dissipate the small amount of heat generated by the fuse during normal operation. --- ## 4. Dimensional Diagram (Typical) ```text [ Knob ] | | ______|__|______ | | | | <-- Panel Face | [ Body ] | |______| |______| | | [Terminals] ``` ---