The part number **47LAC-250B-R** typically refers to a **High-Voltage Ceramic Disc Capacitor**, often categorized under safety-rated components (Y-Class capacitors). These are commonly used in power supply circuits for electromagnetic interference (EMI) suppression. --- ### 1. Technical Specifications Below is a breakdown of the typical technical parameters for this component: | Parameter | Specification (Typical) | | :--- | :--- | | **Capacitance** | 25pF to 4700pF (Depends on series) | | **Voltage Rating** | 250V AC (RMS) | | **Safety Class** | Y2 / X1 | | **Tolerance** | ±10% (K) or ±20% (M) | | **Temperature Coeff.** | Y5P, Y5U, or Y5V | | **Termination** | Radial Leaded | | **RoHS Status** | Compliant (-R suffix) | --- ### 2. Part Number Breakdown While nomenclature varies slightly by manufacturer (such as **Murata** or **TDK** style clones), the code generally breaks down as follows: * **47**: Often represents the capacitance value base. * **L**: High voltage/Safety designation. * **AC**: Designed for Alternating Current (AC) line applications. * **250**: Rated voltage (250V AC). * **B**: Bulk packaging or a specific tolerance/dielectric code. * **-R**: Indicates compliance with **RoHS** (Restriction of Hazardous Substances) standards. --- ### 3. Key Applications These components are specifically engineered for "Line-to-Ground" applications where a failure could lead to electric shock. 1. **EMI/RFI Filtering**: Suppressing noise in switching power supplies. 2. **Antenna Coupling**: Isolating user-accessible parts from high-voltage circuitry. 3. **Line Bypass**: Diverting transient surges to the ground. 4. **Power Adapters**: Found in almost all laptop bricks and phone chargers to meet safety regulations. --- ### 4. Safety Class Significance As a **Y2** rated capacitor, this part is designed to be "fail-safe." If the capacitor fails, it is designed to fail **open** rather than shorted, preventing the chassis of a device from becoming "live" with electricity and causing a lethal shock to the user.