## MF-RHT1300-2: Electronic Overview The **MF-RHT1300-2** is a specific model of Polymer Positive Temperature Coefficient (PPTC) resettable fuse manufactured by **Bourns**. It is part of the MF-RHT series, which is specifically designed for high-temperature environments, such as automotive or industrial applications. --- ### 1. Key Technical Specifications The following table outlines the critical electrical parameters for the MF-RHT1300-2: | Parameter | Specification | Description | | :--- | :--- | :--- | | **Hold Current ($I_{hold}$)** | 13.0 Amps | The maximum current the device will pass without tripping at 23°C. | | **Trip Current ($I_{trip}$)** | 23.4 Amps | The minimum current at which the device will switch to a high-resistance state. | | **Max Voltage ($V_{max}$)** | 16 Volts | The maximum voltage the device can withstand without damage. | | **Max Current ($I_{max}$)** | 100 Amps | The maximum fault current the device can safely interrupt. | | **Power Dissipation ($P_d$)** | 6.9 Watts | Typical power dissipated when the device is in a tripped state. | | **Operating Temp Range** | -40°C to +125°C | Designed for high-heat durability. | --- ### 2. Physical Characteristics & Packaging * **Form Factor:** Through-hole radial leaded package. * **Material:** Conductive polymer matrix. * **Suffix "-2":** In Bourns nomenclature, the suffix **-2** typically indicates that the part is supplied on **Tape and Reel** (kinked leads) for automated assembly, rather than bulk packaging. * **Lead Type:** Kinked leads are often used to ensure a specific seating height on the PCB during soldering. --- ### 3. How It Functions The MF-RHT1300-2 acts as a self-repairing circuit protector: 1. **Normal State:** The polymer contains conductive particles (carbon black) that form a low-resistance path, allowing current to flow to the load. 2. **Fault Condition:** If an overcurrent or overtemperature event occurs, the internal $I^2R$ heating causes the polymer to expand. 3. **Tripped State:** The expansion breaks the conductive chains, causing the resistance to increase exponentially. This limits the current to a safe leakage level. 4. **Reset:** Once the fault is cleared and the device cools down, the polymer contracts, the conductive paths reconnect, and the device returns to a low-resistance state. --- ### 4. Typical Applications Due to its high hold current (13A) and high-temperature rating (125°C), this part is commonly used in: * **Automotive Electronics:** Engine control modules, cooling fan motors, and lighting circuits. * **Industrial Controls:** Protection for heavy-duty sensors and actuators. * **Power Supplies:** Secondary side protection for high-output DC power sources.