Overview of Various Types of Capacitors

1.Polypropylene Capacitor (CBB)

Nominal Capacitance: 1000pF–10μF

Rated Voltage: 63V–2000V

Characteristics: Metallized polypropylene film, low loss at high frequency, inherently low temperature rise, flame-retardant epoxy powder coating (UL94/V-0).

Applications: Used as a replacement for polystyrene or mica capacitors in high-demand circuits.

Walson Capacitor boasts the following features: high stability, high consistency, cost-effectiveness, short lead times, and customization options. With over 25 years of expertise in film capacitors, we possess extensive product application experience.

2.Ceramic Capacitor

Manufacturing Process: Silver metal layers are plated on both sides of a thin ceramic disc.

Advantages: Compact size, high voltage resistance, low cost, excellent high-frequency characteristics (some models are specifically designed for high-frequency applications). Ceramic capacitors perform well in high-frequency circuits but have a maximum capacitance of only 0.1μF. They are a type of ceramic capacitor.

Disadvantages: Low mechanical strength, prone to cracking, and relatively small capacitance.

Applications: High-frequency oscillation, resonant circuits, decoupling, and audio systems.

3.Monolithic Capacitor (Multilayer Ceramic Capacitor, MLCC)

Smaller in size compared to CBB capacitors, with similar characteristics but some inductive reactance.

Uses: Widely used in precision electronic instruments, small electronic devices for resonance, coupling, filtering, and bypassing. Also used in analog/digital signal bypassing and filtering, as well as audio equipment. Can be interchanged with CBB capacitors in non-precision applications.

Features: High stability, low temperature coefficient, capacitance up to 1μF, long lifespan, low equivalent DC resistance, but slightly higher cost.

Disadvantages: Larger temperature coefficient may cause frequency drift in oscillating circuits.

Classification:

Type I: Excellent performance but small capacitance (typically <0.2μF).

Type II: Larger capacitance but slightly inferior performance.

4.Aluminum Electrolytic Capacitor

Nominal Capacitance: 0.47μF–10000μF

Rated Voltage: 6.3V–450V

Characteristics: Compact size with large capacitance, but higher loss and leakage current.

Applications: Power supply filtering, low-frequency coupling, decoupling, and bypassing.

5.Tantalum Electrolytic Capacitor (CA) & Niobium Electrolytic Capacitor (CN)

Nominal Capacitance: 0.1μF–1000μF

Rated Voltage: 6.3V–125V

Characteristics: Lower loss and leakage current compared to aluminum electrolytic capacitors.

Applications: Used in high-precision circuits as a replacement for aluminum electrolytic capacitors.

Monolithic and ceramic capacitors are non-polar (no positive/negative terminals). Only electrolytic capacitors have polarity, marked with "+" or "-" on the casing. In the past, the longer lead indicated the positive terminal, but this method is outdated and no longer used.

Design Considerations:

1.Series Connection of Electrolytic Capacitors: Balancing resistors must be added to ensure voltage across each capacitor remains within the rated range.

2.Explosion Vent Design: No traces should run above the capacitor’s vent on the PCB, and a clearance of ≥2mm must be maintained.

3.Electrolyte Risk: The electrolyte is flammable and conductive. Contact with PCB traces may cause corrosion, leading to short circuits or fires. Therefore, no traces should be placed under the capacitor.

4.Heat Source Isolation: Avoid placing heat-generating components near or directly under electrolytic capacitors.

5.Capacitor Polarity: Aluminum electrolytic capacitors have polarity—reverse voltage or AC voltage must not be applied. Use non-polar capacitors in circuits where reverse voltage may occur.

6.Capacitor Selection: For rapid charging/discharging applications, avoid aluminum electrolytic capacitors. Instead, use specially designed capacitors with longer lifespans.