The **MF-RHT600** is a high-temperature, radial-leaded **Polymeric Positive Temperature Coefficient (PPTC)** resettable fuse manufactured by Bourns. These components are commonly referred to as "resettable fuses" or "polyfuses." --- ## 1. Technical Specifications The "600" in the part number typically refers to the hold current (6.0 Amps). Below are the key electrical characteristics: | Parameter | Specification | | :--- | :--- | | **Hold Current ($I_{hold}$)** | 6.0 Amps | | **Trip Current ($I_{trip}$)** | 10.8 Amps | | **Rated Voltage ($V_{max}$)** | 16 Volts | | **Max Current ($I_{max}$)** | 100 Amps | | **Operating Temp Range** | -40°C to +125°C | | **Power Dissipation** | 4.5 Watts (typical) | --- ## 2. Key Features The **MF-RHT** series is specifically engineered for environments where standard PPTCs might fail due to heat. * **High Temperature Materials:** Unlike standard resettable fuses that operate up to 85°C, the RHT series uses advanced thermal polymers allowing it to function reliably up to **125°C**. * **Resettable Functionality:** After the fault (overcurrent) is removed and the power is cycled, the device cools down and returns to a low-resistance state, avoiding the need for manual replacement. * **Radial Leaded Package:** Designed for through-hole PCB mounting. --- ## 3. How It Works The MF-RHT600 functions based on the physical properties of its conductive polymer: 1. **Normal State:** The conductive particles inside the polymer form low-resistance paths, allowing current to flow freely. 2. **Fault State (Overcurrent):** When current exceeds the limits, $I^2R$ heating causes the polymer to expand. 3. **Tripped State:** The expansion breaks the conductive paths, increasing resistance exponentially and "choking" the current flow to a trickle. 4. **Reset:** Once the short circuit is fixed and heat dissipates, the polymer contracts, re-establishing the conductive paths. --- ## 4. Common Applications Due to its high thermal tolerance, the MF-RHT600 is primarily used in: * **Automotive Electronics:** Near engine compartments or high-density dashboards. * **Industrial Controls:** Equipment subjected to high ambient heat. * **Power Supplies:** Protection for DC motors and fans. * **Telecommunications:** Protection against power cross and lightning surges in harsh environments.