### MF-RHT070-2: Technical Overview The **MF-RHT070-2** is a High-Temperature Polymer Positive Temperature Coefficient (PPTC) resettable fuse manufactured by **Bourns**. It belongs to the Multifuse® series, specifically designed for applications where operating temperatures are elevated. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Hold Current ($I_{hold}$)** | 0.70 Amps | | **Trip Current ($I_{trip}$)** | 1.40 Amps | | **Rated Voltage ($V_{max}$)** | 30 Volts (DC) | | **Max Current ($I_{max}$)** | 40 Amps | | **Operating Temperature** | -40 °C to +125 °C | | **Packaging** | Tape & Reel (indicated by the "-2" suffix) | | **Mounting Type** | Through-Hole (Radial Leaded) | --- ### 2. Core Functional Characteristics #### How it Works The device acts as a non-linear resistor. Under normal conditions, it maintains a very low resistance. When a fault (overcurrent) occurs, the internal polymer heats up, expands, and its resistance increases dramatically, effectively "opening" the circuit to protect downstream components. #### Self-Resettability Unlike a traditional one-shot fuse, the MF-RHT070-2 does not need replacement after a fault. Once the power is removed and the device cools down, the polymer contracts, and the fuse returns to a low-resistance state. #### High-Temperature Performance The "HT" in the part number signifies **High Temperature**. While standard PPTCs trip prematurely in hot environments, this model is engineered to maintain its hold current even in ambient temperatures up to **125 °C**, making it ideal for under-the-hood automotive or industrial applications. --- ### 3. Physical Layout and Materials The device is a radial-leaded component. The structure consists of: * **Conductive Polymer:** The core sensing material. * **Lead Material:** Tin-plated copper. * **Insulation:** Flame-retardant epoxy polymer (meeting UL 94V-0 requirements). --- ### 4. Common Applications * **Automotive:** Engine control modules, cooling fan motors, and sensors. * **Industrial:** Power supplies and motor controllers operating in harsh environments. * **Telecommunications:** Protection for equipment exposed to high ambient heat.