[Physics Class Notes] on Capacitor Types Pdf for Exam

The capacitor is a device that has the ability or “power” to store energy in the form of an electrical charge that creates a potential difference (Static Voltage) through its plates, much like a small rechargeable battery. There are many types of capacitors available from very small capacitor beads that use resonance circuits to large power factor correction capacitors, but they all do the same, they store charge. In other words, the capacitor is an electronic component whose function is to store electrical charges. It is made of two conductors separated by a dielectric film. These plates accumulate electrical charges when connected to a power source. 

They are often storage sites for analogue signals and digital data. In general, comparisons between the different types of capacitors are made concerning the dielectric used between the plates. Some capacitors look like tubes, small capacitors are often made from ceramic materials and then dipped into an epoxy resin to seal them. Below are some of the more common types of capacitors available.

Capacitor Types 

The types of capacitors available range from very small, delicate trimming capacitors used in oscillators or radio circuits, to large-scale metal-type capacitors used in high-voltage power correction and smoothing circuits. 

The comparison between the different types of capacitors is generally made concerning the dielectric used between the plates. Unlike resistors, there are also various types of capacitors that allow us to vary their capacitance value for use in radio or “frequency tuning” style circuits.

 

Some of the capacitors appear like tubes since the metal foil plates are rolled up into a circle to make a small bundle with the insulating dielectric layer sandwiched between them.

Small capacitors are often made from ceramic materials and then immersed in epoxy resins to seal them. Either way, capacitors play an important role in electronic circuits, so here are some of the more “common” types of capacitors available.

Applications of Capacitors

Capacitors have been used in both physical and electronic devices. They are used in filter applications, energy storage systems, engine starters, and signal processing equipment.

Four Types of Capacitors

1. Film Capacitors:

Film capacitors are the most widely prepared of a variety of types of capacitors, consisting of a relatively expansive category of capacitors defining their dielectric properties. They are available in almost any weight and voltages up to 1500 volts. They vary in any tolerance from 10% to 0.01%. In addition, film capacitors come in a variety of shapes and case types. There are two types of film capacitors, the type of radial lead and the type of axial lead. The film capacitor electrodes may be metallic aluminum or zinc, mounted on one or both sides of the plastic film, resulting in metallic film capacitors called film capacitors. The film capacitor is shown in the following figure:

2. Ceramic Capacitors:

Ceramic capacitors are used in high-frequency circuits such as RF audio. They are also the best alternative for high-frequency compensation for audio circuits. These capacitors are also called disk capacitors. Ceramic capacitors are made by coating two sides of small silver porcelain or ceramic disk and then stacked together to make a capacitor. Low capacitance and high capacitance in ceramic capacitors can be achieved by changing the thickness of the ceramic disk used.

3. Electrolytic Capacitors:

These are the most widely used capacitors with a wide tolerance capacity. Electrolytic capacitors are obtainable with working voltages of up to 500V, although high capacitance values are not accessible at high voltage and higher temperature units are not normal. Two types of electrolytic capacitors, Tantalum, and Aluminum are common. Electrolytic capacitors are categorized based on their dielectric.

• Aluminum electrolytic capacitors – aluminum oxide ( dielectric).

• Tantalum electrolytic capacitors – tantalum pentoxide (dielectric).

• Niobium electrolytic capacitors – niobium pentoxide ( dielectric).

4. Variable Capacitors: 

Among the different types of capacitors are a Variable Capacitor, which is one whose capacity can be changed mechanically intentionally, and repeatedly. This type of capacitor was used to set the resonance frequency in LC circuits, e.g. to adjust the radio for impedance matching in antenna tuner devices.

What are Common Capacitors?

Capacitors are mainly divided into two mechanical groups:

• Fixed capacitors

• Variable capacitors

Some common capacitors and their names are mentioned in the table below.

Capacitor Types and Use

The easiest design of the capacitor is the use of two parallel metal plates separated by an insulation layer called a dielectric.

How Capacitor Works

To begin, we can see that a metal contains an equal number of positively and negatively charged particles, indicating that it is electrically neutral. When we connect a power source or a battery to the capacitor’s metal plates, a current or electrons will attempt to travel from the plate connected to the positive lead of the battery to the plate connected to the negative lead of the battery. However, because of the dielectric between the plates, electrons will not be able to travel through the capacitor and will begin to accumulate on the plate. Because of the repulsion of those electronics that are already on the plate, the battery will have insufficient energy to push any more electronics into the plate once a certain number of electronics have collected on the plate. The capacitor is fully charged at this stage. The first plate has generated a net negative charge, and the second plate has produced an equal net positive charge, resulting in an electric field with an attractive office between them that maintains the capacitor’s charge. 

Main Functions of Capacitor

A capacitor is an electrical component that stores and releases electricity in a circuit. It frequently sends alternating current instead of direct current. As a fundamental component of electrical equipment, a capacitor is usually always present in electronic circuits. The capaci
tor’s fundamental function is to store electrostatic energy in an electric field and, if feasible, to supply this energy to the circuit. To avoid a fatal circuit failure, they allow the AC to flow but restrict the DC from flowing. A capacitor can store electric energy when connected to its charging circuit. When unplugged from its charging circuit, it will discharge the collected energy, allowing it to be used like a temporary battery. The most typical application for capacitors is energy storage. Other uses include power condition, signal coupling or decoupling, electrical noise filtering, and remote sensing. Because of their numerous applications, capacitors are employed in a wide range of sec optics and have become an essential part of daily life.