Aluminum Electrolytic Capacitors
Aluminum Electrolytic Capacitors deliver the industry’s best cost-per-farad for energy storage and smoothing in power electronics. Each device uses an etched aluminum anode with an electrochemically grown aluminum-oxide dielectric only nanometres thick, paired with a liquid, polymer, or hybrid electrolyte that serves as the cathode. This structure enables very high capacitance in compact packages for AC-to-DC supplies, DC-DC converters, motor drives, and industrial inverters.
Our portfolio spans SMD (V-chip), radial, axial, snap-in, and screw-terminal styles, with capacitance from sub-microfarads to several farads and voltage ratings from 4 V to 630 V. For classic bulk filtering and wide voltage coverage, choose non-solid (wet) aluminum electrolytics. For high-frequency rails and tight ripple targets, polymer or hybrid polymer capacitors provide exceptionally low ESR and high ripple capability. We also stock bipolar/non-polar types for AC signal applications like audio crossovers.
Selecting the right capacitor is straightforward with our parametric filters for capacitance, voltage, ESR/impedance, ripple current, life rating, temperature, size, and lead spacing. You’ll find trusted brands including Nichicon, Nippon Chemi-Con (UCC), Rubycon, Panasonic, Vishay, Cornell Dubilier (CDE), KEMET/TDK, EPCOS, Jianghai, Lelon, and more—each backed by datasheets, compliance documents, and rapid RFQ support.
Whether you are refreshing an obsolete part, designing a robust 105 °C/125 °C power stage, or building a high-energy DC-link, our catalog helps you compare options quickly and select the best aluminum electrolytic capacitor for performance, lifetime, and total cost.
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- Ultra-low ESR (35mΩ) for high efficiency
- High ripple current (4.21A) handles power demands
- Extended 2000-hour lifespan at 105°C
What are Aluminum Electrolytic Capacitors?
Aluminum electrolytic capacitors are polarized capacitors that achieve very high capacitance by using a roughened aluminum anode foil and an ultra-thin aluminum-oxide (Al₂O₃) dielectric grown by anodization. A conductive electrolyte functions as the cathode, making intimate contact with the etched oxide surface to maximize effective plate area. Because the dielectric is formed electrochemically, these parts offer unmatched capacitance-per-volume at low cost—ideal for energy storage, decoupling, and smoothing in power electronics.
Most devices are polarized and must be used with correct DC polarity. Where true AC operation is required (e.g., audio crossovers), bipolar/non-polar electrolytics use a back-to-back anode configuration so they can tolerate alternating voltages.
Electrolyte Families
Aluminum electrolytics are commonly grouped by electrolyte system:
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Non-solid (liquid/wet): classic “wet” capacitors using glycol/organic/water-based solvents. Widest range of capacitance (≈0.1 µF to several farads) and voltage (≈4 V to 630 V), very cost-effective, and tolerant of transient spikes. Over years, electrolyte loss raises ESR and reduces capacitance, defining service life.
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Solid MnO₂: manganese-dioxide cathode. Better stability than wet types but more sensitive to surge/overstress than liquids.
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Solid Polymer: conductive polymer cathode delivers ultra-low ESR, high ripple current capability, and excellent high-frequency performance—popular in modern SMPS and CPU VRMs. Voltage range is typically lower than wet types.
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Hybrid Polymer: combine polymer with a small amount of liquid electrolyte to balance low ESR with good self-healing/low leakage, increasingly common in demanding automotive and industrial designs.
Form Factors & Mounting Styles
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SMD (V-chip) for reflow assembly in compact electronics.
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Radial leaded (single-ended) for general purpose boards.
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Axial leaded for horizontal, through-hole layouts and service replacements.
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Snap-in for medium/high-power supplies; fast board assembly.
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Screw-terminal (can types) for DC-link and high-energy storage in drives, UPS, and inverters.
Why Choose Aluminum Electrolytics?
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Very high capacitance density for bulk storage and low-frequency filtering (50/60 Hz).
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Attractive $/F and broad availability.
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Self-healing oxide supports long service when operated within ratings.
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Product families optimized for low-ESR, high ripple current, long life (up to 10,000–20,000 h at 105 °C), high temperature (125 °C), or automotive AEC-Q200 compliance.
Inherent Considerations
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Polarized (except bipolar types); reverse bias or AC on polarized parts can cause gas generation and failure.
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End-of-life driven by electrolyte loss: capacitance decreases, ESR increases. Life roughly doubles for every 10 °C decrease in core temperature (Arrhenius “10-degree rule”).
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ESR/impedance are frequency and temperature dependent; polymer/hybrid excel at high-frequency ripple.
Typical Applications
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Input/output smoothing in linear and switch-mode power supplies (SMPS).
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DC-link capacitors in motor drives, inverters for PV/wind, and UPS systems (snap-in/screw terminal).
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DC-DC converters (bulk storage and ripple handling).
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Energy pulse applications (photoflash/strobe, welders—specialized high-voltage types).
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Audio coupling/bypass (use bipolar electrolytics for AC paths).
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General decoupling in industrial controls, telecom, and instrumentation.
How to Select the Right Aluminum Electrolytic Capacitors
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Capacitance (C) & Voltage (V)
Choose C to meet ripple and hold-up targets. Select rated voltage with margin above worst-case operating voltage (commonly 20–50%). For high temps, also check category voltage if specified. -
Ripple Current (Irms)
Ensure the capacitor’s rated ripple current at operating temperature/frequency exceeds the circuit’s RMS ripple. Remember ripple heating scales with I²·ESR; higher Irms or lower ESR reduces core temperature rise. -
ESR & Impedance (Z)
For high-frequency SMPS rails, polymer or hybrid aluminum electrolytics provide much lower ESR than wet types and reduce the number of parallel parts. -
Lifetime/Endurance
Compare load-life (e.g., 2,000/5,000/10,000 h at 105 °C) and use life calculators/curves to estimate life at your actual core temperature. Lower ambient, good airflow, and spacing from heat sources dramatically extend life. -
Temperature Rating
85 °C general purpose; 105 °C is now a common baseline; 125 °C series exist for under-hood and harsh industrial. -
Size & Mounting
SMD for compactness; radial for universal use; snap-in for 200–500 V bulk; screw-terminal for multi-kW DC-links. -
Special Requirements
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Bipolar for AC signal paths.
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AEC-Q200 for automotive.
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Low-leakage for hold-up or battery systems.
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Safety vent orientation and mounting for large cans; leave clearance for vent operation.
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Design Tips & Good Practices
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Thermal management: Board airflow, heat-spreading planes, and distance from hot inductors/HS sinks reduce core temperature and multiply lifetime.
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Parallel/series: Paralleling reduces ESR and shares ripple; series connection for higher voltage requires balancing resistors to equalize voltage.
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Surge/Transients: Wet types handle short spikes better; observe surge voltage limits and inrush control where needed.
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Polarity & Markings: Minus stripe (wet) or plus marking (solid) identifies terminals; verify PCB silkscreen.
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Storage & Re-use: Modern parts have excellent shelf life; follow datasheet if reforming is recommended for older stock.
Popular Manufacturers & Families
We source from global leaders to match every budget and performance target:
Nichicon, Nippon Chemi-Con (UCC), Rubycon, Panasonic, ELNA, Lelon, Jamicon, Jianghai, WÜRTH Elektronik, Vishay, Cornell Dubilier (CDE), KEMET/TDK, EPCOS (TDK), Samwha, Illinois Capacitor, Sunon/NIC (for catalog brands), and specialized suppliers of polymer/hybrid series.
For ultra-low-ESR polymer/hybrid needs, explore Panasonic OS-CON/SP-Cap, Nichicon FPCAP/FP-series, Chemi-Con AP/PS series, Rubycon ZLJ/ZLH/Polymer lines, and CDE/TDK long-life snap-ins for DC-link use.
Why Buy Here?
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Parametric filters for capacitance, voltage, ESR, ripple, size, life.
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Datasheets, RoHS/REACH, and cross-references for drop-in replacements.
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RFQ & volume pricing, with stocking options for production and maintenance spares.
FAQ (SEO-friendly with long-tail keywords)
Q1. What are aluminum electrolytic capacitors used for in power supplies?
They provide bulk energy storage and ripple smoothing on the AC-to-DC rectifier output and on DC-DC rails. For example, choosing a 2200 µF 25 V low-ESR aluminum electrolytic capacitor for a 12 V SMPS reduces output ripple and improves transient response.
Q2. Wet vs. polymer aluminum electrolytic—what’s the difference?
Wet (liquid) capacitors offer the broadest voltage range up to ~630 V and excellent surge tolerance at low cost. Polymer aluminum electrolytic capacitors deliver very low ESR/high ripple current and superior high-frequency performance, ideal for VRM and high-speed DC-DC converters, but with lower maximum voltage ratings.
Q3. Can I replace an 85 °C capacitor with a 105 °C part?
Yes—105 °C or 125 °C aluminum electrolytic capacitors typically offer longer lifetime at the same operating conditions. Always keep capacitance, voltage, ESR, can size, and lead spacing compatible.
Q4. What is a bipolar (non-polar) aluminum electrolytic capacitor used for?
Bipolar electrolytics are designed for AC signal paths such as audio crossover capacitors or motor run circuits where voltage reverses. Search “bipolar electrolytic capacitor for audio” to find value/voltage options.
Q5. How do I size ripple current for a DC-link capacitor?
Sum the RMS ripple components from the inverter/rectifier, then select a snap-in or screw-terminal electrolytic capacitor with sufficient Irms at 105 °C, allowing thermal margin. Many engineers parallel multiple 400–500 V snap-ins to meet both capacitance and ripple current.
Q6. What does “low-ESR aluminum electrolytic capacitor 12 V” mean?
“Low-ESR” indicates reduced internal resistance, lowering ripple voltage and self-heating—important in 12 V automotive and PC power rails. Consider polymer or “ultra-low-impedance” wet series where high ripple is present.
Q7. Are aluminum electrolytic capacitors good for LED drivers and HVAC controls?
Yes—choose long-life 105 °C/125 °C, high-ripple series for LED power supplies, HVAC fan drives, and industrial PLCs. For elevated ambient temperatures, derate voltage and verify lifetime at expected core temperature.