The **125LD15-R** is a high-voltage, disc-type ceramic capacitor manufactured by **Vishay Cera-Mite**. It is part of the 125L series, specifically designed for high-reliability applications involving high AC and DC voltages. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Part Number** | 125LD15-R | | **Capacitance** | 1500 pF (1.5 nF) | | **Voltage Rating** | 125 kVDC / 30 kVAC (approximate series range) | | **Tolerance** | ±20% (Standard for this series) | | **Temperature Coefficient** | N4700 (Class 1 ceramic) | | **Mounting Type** | Through-hole (Radial Disc) | | **Coating** | Flame-retardant epoxy (UL 94 V-0) | --- ### 2. Physical and Material Composition * **Ceramic Dielectric:** It utilizes **N4700** strontium-based ceramic material. This provides excellent stability with low dissipation factors and minimal capacitance change under varying voltage and temperature conditions. * **Electrodes:** Usually consists of silver-plated electrodes fired onto the ceramic disc. * **Lead Wires:** Tinned copper wires designed for secure soldering onto PCBs or terminal blocks. * **Encapsulation:** The body is encapsulated in a hard, blue or tan epoxy resin that protects against moisture and electrical arcing. --- ### 3. Features and Applications #### Features: * **Low Dissipation Factor:** Ensures minimal energy loss as heat. * **High Insulation Resistance:** Crucial for safety and performance in high-voltage circuits. * **Low Inductance:** The disc geometry allows for high-frequency performance. #### Typical Applications: 1. **High Voltage Power Supplies:** Used for filtering and energy storage. 2. **X-Ray Machines:** Managing pulse generation and stabilization. 3. **Lasers:** Serving as part of the charging/discharging circuitry. 4. **Voltage Multipliers:** Used in "Cockcroft-Walton" generator circuits to step up AC voltage to high DC levels. --- ### 4. Part Number Breakdown The nomenclature generally follows this logic: * **125L:** Series identifier (High voltage ceramic). * **D:** Disc type construction. * **15:** Represents the capacitance value (often uses a 3-digit code where 151 = 150pF, but in this specific legacy series, it maps to the 1500pF range depending on physical size). * **-R:** Indicates compliance with RoHS (Restriction of Hazardous Substances) standards.