The **MF-RX110/72** is a specific electronic component belonging to the **Resettable PTC (Positive Temperature Coefficient) Fuse** family, manufactured by **Bourns**. These are often referred to as "Multifuses." --- ## 1. Core Technical Specifications The part number encodes specific data about its electrical behavior and physical tolerances. | Parameter | Value / Description | | :--- | :--- | | **Hold Current ($I_{hold}$)** | 1.10 Amps (The current at which the device will not trip) | | **Trip Current ($I_{trip}$)** | 2.20 Amps (The current at which the device is guaranteed to trip) | | **Max Voltage ($V_{max}$)** | 72 Volts (Maximum voltage the device can withstand without damage) | | **Max Current ($I_{max}$)** | 40 Amps (Maximum fault current the device can safely interrupt) | | **Typical Power ($P_d$)** | 1.50 Watts | | **Termination Style** | Through-hole (Radial Leaded) | --- ## 2. How it Works Unlike a standard one-time fuse that melts and must be replaced, the MF-RX110/72 acts as a self-repairing circuit breaker: 1. **Normal State:** The internal conductive polymer allows current to flow with very low resistance. 2. **Fault State (Overcurrent):** Excessive current causes internal heating. Once the temperature reaches a threshold, the polymer expands and shifts to a high-resistance state, effectively cutting off the circuit. 3. **Reset State:** Once the fault is removed and the power is cycled (or the device cools down), the polymer contracts, and the device returns to a low-resistance state. --- ## 3. Physical Attributes The "RX" series typically features a circular or rectangular "tear-drop" shape coated in flame-retardant epoxy. ```yaml Component: Radial Leaded PTC Material: Carbon-doped Polymer Coating: Cured, flame retardant epoxy (meets UL 94V-0) Lead Material: Tin-plated copper ``` --- ## 4. Typical Applications Because of its **72V rating**, this specific model is popular in industrial and telecommunications equipment where voltage spikes may occur. * **Security Systems:** Protecting sensors and control panels. * **Industrial Controls:** Protecting PLCs and motors. * **Power Supplies:** Short-circuit protection for DC power rails. * **Transformers:** Protection against secondary side overcurrent. ---