The part number **DM05EY151DO3-SA-R02** refers to a high-precision **Mica Capacitor**, typically manufactured by companies like **Cornell Dubilier (CDE)** or similar specialty passive component manufacturers. These capacitors are renowned for their stability, low loss, and high reliability in RF and precision timing circuits. --- ## 1. Technical Specifications The part number is an alphanumeric code representing the physical and electrical characteristics of the component. | Specification | Value / Description | | :--- | :--- | | **Component Type** | Silver Mica Capacitor | | **Capacitance** | 150 pF (Picofarads) | | **Tolerance** | ±0.5 pF (Indicated by 'D') | | **Voltage Rating** | 500V DC (Standard for DM05 series) | | **Temperature Range** | -55°C to +125°C | | **Case Style** | Dipped Mica (Radial Leads) | | **Case Size** | DM05 (Smallest standard size) | --- ## 2. Component Breakdown The nomenclature can be broken down as follows: * **DM05**: Refers to the physical case size and style (Dipped Mica, Size 05). * **EY**: Indicates the characteristic/temperature coefficient (stability over temperature). * **151**: The capacitance code. The first two digits are significant (15), and the third is the multiplier ($10^1$). $15 \times 10 = 150\text{ pF}$. * **D**: The tolerance code. For values below 10pF, it means ±0.5pF; for higher values, it usually indicates a very tight precision percentage. * **O3**: Internal manufacturer designator for lead spacing or finish. * **SA-R02**: RoHS compliance markers and packaging variations (e.g., bulk vs. tape). --- ## 3. Key Electronic Characteristics Mica capacitors like the DM05 series are chosen over ceramic or electrolytic types for specific electronic reasons: ### A. High Stability Mica is a natural mineral that does not change dimensionally or electrically with age. This ensures the capacitance remains exactly 150pF for decades. ### B. Low Dissipation Factor (High Q) They have extremely low losses at high frequencies. This makes them ideal for **RF (Radio Frequency)** applications where "Quality Factor" (Q) is critical to filter sharpness. ### C. Precision Tolerance With a "D" tolerance (±0.5 pF), this part is intended for circuits where even a 1% deviance could cause a frequency shift, such as in oscillators or tuned amplifiers. --- ## 4. Common Applications * **RF Oscillators:** Maintaining a stable carrier frequency. * **Tuned Circuits:** Used in ham radio equipment, transmitters, and receivers. * **Pulse Handling:** Because mica can handle high $dV/dt$ (rapid voltage changes) without degrading. * **Calibration Equipment:** Used as a reference standard in measurement tools.