The part number **500-200-R** is a specific electronic component most commonly associated with **Bel Fuse Inc.** It belongs to their series of **PTC (Positive Temperature Coefficient) Resettable Fuses**. --- ## 1. Component Overview The 500-200-R is a radial-leaded resettable fuse used for overcurrent protection. Unlike traditional fuses that blow and must be replaced, these "reset" themselves once the fault condition is removed and the temperature drops. ### Technical Specifications | Parameter | Value | | :--- | :--- | | **Manufacturer** | Bel Fuse Inc. | | **Series** | 0ZRE Series | | **Hold Current ($I_{hold}$)** | 2.00 Amps | | **Trip Current ($I_{trip}$)** | 4.00 Amps | | **Maximum Voltage ($V_{max}$)** | 60V (DC or AC) | | **Maximum Current ($I_{max}$)** | 40 Amps | | **Typical Power ($P_d$)** | 1.5 Watts | | **Mounting Type** | Through-hole (Radial Leads) | --- ## 2. Key Features * **Resettable Protection:** Automatically restores circuit operation after a trip event and power cycle. * **Operating Temperature:** Typically rated for operation between **-40°C to +85°C**. * **Standard Compliance:** Usually RoHS compliant (indicated by the "-R" suffix) and UL recognized. * **Fast Trip Time:** Designed to react quickly to surges to prevent damage to downstream sensitive components. --- ## 3. How It Works The device is made of a conductive polymer composite. 1. **Normal State:** The polymer is in a crystalline state, and the carbon particles form paths for current to flow with low resistance. 2. **Fault State:** When excessive current flows, the polymer heats up and expands into an amorphous state. 3. **Protection:** This expansion breaks the carbon paths, causing the resistance to increase dramatically, effectively "opening" the circuit. 4. **Reset:** Once the power is removed and the device cools, the polymer contracts, paths reform, and the fuse returns to a low-resistance state. --- ## 4. Typical Applications * **Industrial Controls:** Protecting PLCs and sensor loops. * **Computer Peripherals:** USB ports and plug-and-play interfaces. * **Power Supplies:** Low-voltage transformers and battery packs. * **Consumer Electronics:** Protecting motors or fans from stalling/overheating.