The classification of electrolytic capacitors is mainly based on factors such as material, structure, and electrolyte morphology. The following are common classification methods and their characteristics:
Classified by electrode material
(1) Aluminum electrolytic capacitor
Characteristics:
Large capacity (μ F to tens of thousands of μ F), wide voltage withstand range (several volts to hundreds of volts).
Low cost, but large in size and short in lifespan (electrolyte easily dries up).
Poor high-frequency performance and high equivalent series resistance (ESR).
Subdivision type:
Liquid electrolyte aluminum capacitor: traditional type, low price but short lifespan.
Solid state aluminum capacitors: using conductive polymers instead of liquid electrolytes, with lower ESR, longer lifespan, high temperature resistance, but higher cost.
Hybrid aluminum capacitor: liquid electrolyte+polymer material, balancing lifespan and cost.
Applications: power filtering, low-frequency coupling, energy storage (such as power adapters, audio equipment).
(2) Tantalum electrolytic capacitor
Characteristics:
Small size, high capacity density (μ F to several hundred μ F), low voltage resistance (usually<50V).
Good stability, long lifespan, and superior high-frequency performance compared to aluminum electrolysis.
High cost, sensitive to reverse voltage, and prone to fire due to overvoltage.
Subdivision type:
Manganese dioxide tantalum capacitor: a traditional type that requires series resistance protection and has low voltage resistance.
Conductive polymer tantalum capacitor: lower ESR, stronger high-frequency performance, and improved surge resistance.
Application: Precision circuits, high-frequency filtering (such as mobile phone motherboards, medical equipment).
(3) Niobium electrolytic capacitor
Characteristics:
The performance is similar to tantalum capacitors, but the raw material cost is lower and the environmental friendliness is better.
Slightly lower voltage resistance, with a capacity range similar to tantalum capacitors.
Application: Replace tantalum capacitors in mid to low end scenarios (such as consumer electronics).
Classified by electrolyte form
(1) Liquid electrolytic capacitor
Use liquid electrolyte (such as ammonium borate solution).
Advantages: Low cost, large capacity.
Disadvantages: Easy to leak, short lifespan, high ESR.
Typical: Traditional aluminum electrolytic capacitors.
(2) Solid state electrolytic capacitor
Use conductive polymers or solid electrolytes such as manganese dioxide.
Advantages: No leakage risk, low ESR, long lifespan, high temperature resistance.
Disadvantages: High cost and small capacity.
Typical: Solid aluminum capacitors, polymer tantalum capacitors.
Classified by polarity structure
(1) Polarized electrolytic capacitor
It is necessary to strictly distinguish between positive and negative poles, as reverse voltage can cause damage.
Representative: Aluminum electrolysis, tantalum electrolysis, niobium electrolysis capacitors.
(2) Non-polar electrolytic capacitor
Specially designed electrolytic capacitors can withstand bidirectional voltage.
Features: Small capacity, high cost.
Application: AC circuits (such as speaker dividers).
Classified by packaging form
(1) Direct insertion (plug-in) electrolytic capacitor
The pins are long and suitable for manual soldering or through-hole insertion.
Typical: Cylindrical aluminum electrolytic capacitor (such as used for power filtering).
(2) Surface mount (SMD) electrolytic capacitors
Surface mount design, small size, suitable for automated production.
Typical: Surface mount tantalum capacitors, solid-state aluminum capacitors (such as mobile phone motherboards).
Classified by special purpose
(1) High frequency low resistance electrolytic capacitor
Specially designed to reduce ESR, used for switching power supplies and CPU power supply.
Representative: Solid aluminum capacitors, polymer tantalum capacitors.
(2) Long life electrolytic capacitor
High temperature resistant design (105 ℃~125 ℃), with a lifespan of thousands to tens of thousands of hours.
Applications: Industrial equipment, automotive electronics.
(3) High voltage electrolytic capacitor
Withstand voltage exceeding 400V, used in high-power scenarios such as frequency converters and photovoltaic inverters.
Selection Comparison Table
|Type | Capacity Range | Voltage Endurance Range | ESR | Lifespan | Cost | Typical Applications|
|Liquid aluminum electrolysis | 1 μ F~1F | 6.3V~500V | High | Short (~2000h) | Low | Power filtering and energy storage|
|Solid state aluminum electrolysis | 1 μ F~1000 μ F | 6.3V~100V | Low | Long (>5000h) | Medium high | Mainboard CPU power supply, high-frequency circuit|
|Manganese dioxide tantalum capacitor | 0.1 μ F~1000 μ F | 2.5V~50V | Medium | Long | High | Precision instruments and communication equipment|
|Polymer tantalum capacitor | 1 μ F~470 μ F | 2.5V~35V | Extremely low | Extremely long | Extremely high | Military and aerospace equipment|
|Non polarized electrolytic capacitor | 0.1 μ F~100 μ F |<100V | High | Medium | High | AC signal coupling|
Key precautions
Polarity requirement: Reverse connection of polarized capacitors may cause explosions, and strict differentiation between positive and negative poles is required.
Temperature effect: High temperature will accelerate the drying of liquid electrolyte and shorten its lifespan.
High frequency scenario: Prioritize selecting solid-state or polymer capacitors with low ESR.
Replacement principle: The capacity and withstand voltage need to be matched, and solid-state and liquid capacitors cannot be directly interchanged.
The selection of electrolytic capacitors requires a comprehensive consideration of capacity, withstand voltage ESR、 Balance the lifespan and cost based on specific circuit requirements.