CAPACITORS

A capacitor is a passive electronic device that stores electrical energy by accumulating electric charges on two conductive surfaces, typically metallic plates or surfaces, separated by an insulating material called the dielectric. This configuration allows the capacitor to store charge and release it when needed, making it a fundamental component in energy storage and signal filtering.

How Does a Capacitor Work?

When a voltage is applied across the terminals of a capacitor, an electric field forms across the dielectric, leading to a net positive charge on one plate and a net negative charge on the other plate. Unlike a battery, no current flows through the dielectric itself; however, there is a flow of charge through the source circuit. This results in charging and discharging cycles when a time-varying voltage is applied, creating a continuous current flow through the capacitor.

Types of Capacitors

Capacitors come in various types, each designed for specific applications and performance requirements. Some popular capacitor types include:

• Ceramic Capacitors: These versatile capacitors use a ceramic material as the dielectric, making them ideal for a wide range of applications. They come in different variants, such as leaded disc ceramic capacitors, surface mount multi-layered ceramic capacitors (MLCCs), and microwave bare lead-less disc ceramic capacitors.
• Film Capacitors: Utilizing a polymer film or plastic film dielectric, film capacitors offer several advantages, including low cost and limitless shelf life. They are commonly found in power film capacitors and are available in various voltage ranges.
• Electrolytic Capacitors: Electrolytic capacitors have metallic anodes coated with an oxidized layer, acting as the dielectric. Categorized based on their dielectric materials, they include aluminium electrolytic capacitors, tantalum electrolytic capacitors, and niobium electrolytic capacitors.
• Paper Capacitors: Classic in design, paper capacitors use paper as the dielectric material, precisely storing a fixed amount of electric charge.

How to Choose a Capacitor

Selecting the right capacitor requires careful consideration of several factors:

1. Capacitance Size: Determine the required capacitance value based on the specific application's energy storage needs.
2. Maximum Voltage Rating: Choose a capacitor with a voltage rating that can handle the maximum voltage that will be applied across it.
3. Leakage Current: Consider the capacitor's leakage current, which leads to slow energy drainage.
4. Equivalent Series Resistance (ESR): Check the ESR, which causes heat and power loss at higher currents.
5. Tolerance: Account for the nominal capacitance rating's tolerance, which may vary slightly from the desired value.

Applications of Capacitors

Capacitors find extensive application in various industries, including:

• Energy Storage and Power Conditioning
• Pulsed Power and Power Factor Correction
• Sensors and Coupling
• Tuning and Decoupling
• Suppression and Filters (High-Pass and Low-Pass)
• Noise Filters and Snubbers

Popular Brands that manufacture capacitors

Several renowned brands manufacture high-quality capacitors, including:

• Panasonic Corporation
• Murata Manufacturing Co., Ltd.
• Vishay Intertechnology
• TDK Corporation
• Nichicon Corporation
• KEMET Corporation
• AVX Corporation
• Rubycon Corporation
• Cornell Dubilier Electronics, Inc.
• Samsung Electro-Mechanics