Aluminum electrolytic capacitors are polarized capacitors using an aluminum oxide layer as the dielectric medium. They consist of an aluminum anode, electrolyte solution, and cathode. These capacitors offer high capacitance values (1 F-2.7F) with relatively compact size, making them essential components in power supply filtering, signal decoupling, and energy storage applications. Their evolution has enabled miniaturization in electronics while maintaining performance in harsh environments.
| Type | Functional Characteristics | Application Examples |
|---|---|---|
| Radial Lead Type | Vertical mounting with dual leads | Consumer electronics power supplies |
| SMD Type | Surface-mount design for PCB integration | Computer motherboards |
| Stud Mount Type | High-current screw terminal design | Industrial inverters |
| Bi-polar Type | Able to withstand reverse voltage | Motor drive circuits |
Typical construction includes: - Anode Foil: High-purity aluminum with etched surface (100-600m /m effective area) - Dielectric Layer: 0.1-0.8 m thick aluminum oxide (Al O ) - Electrolyte: Ammonium borate solution in organic solvent - Cathode Foil: 50-100 m aluminum sheet - Separator Paper: 50 m thick kraft paper soaked in electrolyte - Aluminum Case: 0.5-2.0mm thick stamped enclosure
| Parameter | Description | Importance |
|---|---|---|
| Capacitance (C) | 1 F-2.7F (120Hz measurement) | Determines filtering effectiveness |
| Rated Voltage (UR) | 6.3V-630V DC working range | Failure risk above limit |
| ESR | 5m -1.5 at 100kHz | Affects switching performance |
| Ripple Current | 100mA-5A RMS | Lifetime predictor |
| Leakage Current | 0.01C UR A maximum | Power efficiency factor |
| Operating Temp | -55 C to +150 C range | Reliability indicator |
| Manufacturer | Headquarters | Representative Product |
|---|---|---|
| Nichicon | Japan | UPW Series (105 C, 2000h) |
| Rubycon | Japan | ZL Series (Low ESR 4m ) |
| United Chemi-Con | USA | KXJ Series (630V rating) |
| Samxon | Taiwan | EEU-FR Series (Conductive polymer hybrid) |
Consider these factors: - Required capacitance tolerance ( 20% standard) - Voltage derating (select 1.25 operating voltage) - Temperature range (automotive requires -40 C to +150 C) - Vibration resistance (screw-terminal better than SMD) - Lifetime calculation: Lx = L0 (T0/ T) (UR/UX) - RoHS compliance for environmental regulations
Current developments include: - Conductive polymer hybrid capacitors (30% ESR reduction) - Nanoscale dielectric engineering (<0.1 m oxide layers) - AI-driven lifetime prediction models - Bio-compatible electrolyte formulations - 4D printing of anode structures - Integration with PCB substrates
In a 3kW server power supply, 4x 450V/470 F capacitors in parallel provide 2220 F total capacitance with 14Arms ripple current handling. The design uses Nichicon U3 series devices with 6.5mm lead spacing, operating at 120 C with 95% voltage derating, achieving 8000-hour MTBF.