Capacitor Types

Introduction

Capacitors come in a variety of shapes and sizes, but what most people don't realize is that they also have different effects and purposes. While all capacitors can store energy, some are designed to give it back to the circuit quickly while others are meant to hold on to it longer; some are made specifically to filter out high-frequency signals while others focus on low-frequency ones. By knowing the kind of capacitor you’re using and its intended purpose, you can make sure you get the right capacitor for your circuit—and maximize its usefulness in that circuit.

What is Capacitor?

A capacitor is a passive two-terminal electrical component used to store energy in an electric field. A capacitor consists of two electrically conductive plates separated by a dielectric material, typically some form of insulator but organic molecules can also be used. An electric charge on one plate will force electrons through an external circuit, eventually leaving an opposite charge on another plate.

Formula for Capacitor

C = Q/V

Where,

Q = electric charge (coulombs)

C = Capacitance (Farad)

V = Voltage across the plate (Volts)

Classification of Capacitors

The first step in any capacitor purchase is understanding what kind of capacitor you need. There are different types of capacitors available that have different applications and uses. They are available from small delicate trimming capacitors to large power metals.

Classification of capacitors as per the structure

Fixed Capacitors

• Variable Capacitors
• Trimmer Capacitors

Classification of capacitors as per the polarization

• Polarized
• Unpolarized

Understanding how these types of capacitors differ from one another will help you find just what you need.

Ceramic Capacitors

Ceramic capacitors are made from ceramic, an oxide that has very good electrical properties. The insulating layer is most often made of mica or glass; it may also be made with plastic. The conductive surface, or plated surface, is coated with tin oxide—which gives it its conducting properties—and sometimes zinc oxide as well.

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These come in a range of sizes from .001 microfarads to .1 microfarads. All-ceramic capacitors have become quite popular because they work at higher temperatures than other types. Using these capacitors can save you a lot on installation costs as you won’t need additional air conditioning units or fans for cooling them down during warm months.

Application of ceramic

• The non-polarity property makes it sustainable.

• They are used in high-density applications like printed circuit boards.

• They are used in the resonant circuit that is available in transmitters.

Film Capacitors

Compared to ceramic capacitors, film capacitors have a lower dissipation factor. These capacitors also work better at higher frequencies than ceramic ones. Also, they have a limitless shelflife. The film capacitor comes wrapped in a thin film. Film capacitors come in both tantalum (used in high-voltage or high-current applications) and polypropylene varieties. These type of capacitors has an average voltage range of 50 V to 2 kV.

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Uses of Film Capacitors

• They can be found inside some televisions as well as cameras, radios, electronic test equipment, computers, power supplies, and arc lighting circuits.

• Film caps are very small — some fit on microchips — but big ones used in guitar effects pedals can measure several inches across!

Power Film Capacitors

The making process, technique, and materials in the power film capacitors are similar to film capacitors. The only change in power film is a polypropylene film that is used as a dielectric in it.

Power film capacitors can be found in a wide range of applications including consumer products such as televisions and DVD players to a variety of industrial products including washing machines.

Electrolytic Capacitors

These are polarized capacitors typically used to smooth large fluctuations in voltage. They have a very high storage capacity for energy, but can only do so for an extremely short amount of time due to their electrolyte liquid in which conductive plates are submerged. If your circuit needed to store a lot of energy at once, then it would make sense to use electrolytic capacitors; otherwise, you’d be better off with another type.

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They also categories in different capacitors

• Tantalum electrolytic capacitors
• Aluminum electrolytic capacitors
• Niobium electrolytic capacitors

Application of Electrolytic Capacitors

• They can withstand up to several thousand volts while other types cannot hold as much voltage without catching fire.

• Electrolytic capacitors are used in audio amplifiers to reduce electrical noise.

• They maintain their charge almost indefinitely—you could throw them away after three years and unpack them five years later with no loss in electricity retention or ability to charge.

Paper Capacitors

Paper capacitors use activated carbon or another similar material that has been pressed into thin sheets between two metal plates. They are also known as fixed capacitors. The thin layers serve as electrodes for storage of charge, just like in other types of capacitors. This is also called a parallel plate capacitor because it’s made up of multiple plate sheets laid parallel to each other; each plate sheet can conduct electricity independently.

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Application of Paper capacitors

• This capacitor is used in consumer electronics, but electronic circuits becoming smaller.

• They are used in the coupling, decoupling, and noise filtering systems.

• These capacitors are used in audio systems of cars, humidity sensor devices, fuel level sensors devices, etc.

FAQs

Q1. How to analyze the quality of the capacitors?

Ans. The way to analyze whether a capacitor is good or not is to first find out what type it is, then identify its specifications on paper. If you have an ohmmeter or digital multimeter, use that to test if there are any shorts in your capacitors. Connect the negative end of the capacitor to black lead while the positive end connects to the red lead of the multimeter.

The zero reading shows the capacitor is in good condition.

Q2. What are Common Capacitors?

Ans. Commonly used capacitors include aluminum electrolytic, ceramic, film, tantalum polymer, tantalum metalized film, Double-layer capacitors, Hybrid capacitors, Pseudo capacitors, and high voltage electrolytic or tantalum capacitors. They offer good reliability and stability over a wide range of operating temperatures in your budget.

Q3. What is the principle of the capacitor?

Ans. A capacitor is made of two conductive plates separated by an insulator, otherwise known as a dielectric. This separates these two plates electrically while still allowing them to interact with each other.

Q4. Which metal is used in the capacitor?

Ans. A capacitor consists of two or more metallic plates like Alluminium, silver, etc, usually separated by an insulator. The capacitor’s ability to store charge depends on how much area is between these plates and how much voltage is present across them.