What is Capacitor: Definition, Capacitor Symbol, Types

What Is Capacitor: They are simple devices that store electrically charged charges in their plate when connected with the voltage source. A capacitor is a device that can store energy as an electric charge.

What is Capacitor

In comparison to a similar size battery, a capacitor can store a smaller amount of energy, about 10 000 times smaller. However, it is sufficient for many different circuit designs.

It is a device with the capability to “capacity” of storing energy as an electrical charge that creates an electric potential (Static Voltage) across its plates, similar to rechargeable batteries.

There are a variety of available capacitors, from tiny capacitor beads used in resonance circuits to larger Power factor corrector capacitors; however, they all do the same thing. They are used to store charge.

In its simplest structure, a capacitor comprises two or three conducting (metal) plates that aren’t connected or touching one another.

They are separated by air or good insulating material, like waxed papers, ceramic, mica, or any other form of liquid gel employed in electrolytic capacitors.

Capacitor symbol:

Capacitor Symbol

Capacitor Construction:

A capacitor consists of two metal plates separated by an insulating substance called a dielectric. They are both conductive and typically made from tantalum, aluminium or other metallic materials. 

At the same time, dielectrics can be constructed from any material for insulation, including glass, paper, ceramic or any other material that blocks current flow. Check This: How to Stay Focused

Types Of Capacitors:

  1. Electrolytic Capacitor
  2. Mica Capacitor
  3. Paper Capacitor
  4. Film Capacitor
  5. Non-Polarized Capacitor
  6. Ceramic Capacitor

1: Electrolytic Capacitor

Typically, electrolyte capacitors are utilized when big capacitor values are required. The thin layer of film is used as one electrode, and for another electrode (cathode), an electrolyte semi-liquid solution made of paste or jelly is utilized. Dielectric plates are a fine layer of oxide. 

It is produced electrochemically by an amount of film, and it is not more than 10 microns.

2: Mica Capacitor:

The dielectric used in the silver mica capacitors is a natural mineral. There are two kinds of mica capacitors. They have clamped capacitors as well as silver mica capacitors. 

They are regarded as obsolete due to their lack of characteristics. Silver mica capacitors are made by sandwiching mica sheets in metal with both surfaces, and this is then enclosed in epoxy to shield the surrounding environment. 

The mica capacitors are employed to make a robust, stable capacitor of very small size.

3: Paper Capacitor:

The paper capacitor’s structure is built between two sheets of tin foil, removed from paper or oiled paper and then waxed. The two aluminium foils from the capacitors are made of paper are connected to the load externally. 

The thin foils and paper are formed into a cylindrical shape and finally contained in a plastic container.

4: Film Capacitor:

In film capacitors, thin plastic is used as the dielectric. A film capacitor can be made extremely thin by using the advanced process of drawing films.

If the film was made by metalizing, it could depend on the characteristics of the capacitor. To guard against the elements, electrodes are inserted and are arranged.

5: Non-Polarized Capacitors:

Generally, non-polarized capacitors are of two types: plastic foil capacitors and metal foil capacitors. The other is an electrolytic, non-polarized capacitor.

The aluminium foil capacitor is non-polarized. The electrolytic capacitors typically consist of two capacitors in series and are located reverse to reverse, so the non-polarized capacitor with half capacitance. 

The capacitor with no polarization requires AC applications to be in series or parallel to the power supply or signal.

6: Ceramic Capacitor:

As capacitors, ceramic capacitors utilize this material to act as the dielectric. Ceramics were among the first materials used in the manufacturing of capacitors as insulation. Read Also: What Is Centripetal Acceleration Formula

What is the Process of Capacitors classified?

  1. Fixed Capacitors Fixed
  2. Variable Capacitors
  3. Trimmer Capacitors

The Capacitance of the Capacitor:

Capacitance is an electrical property of a capacitor. It is the measurement of a capacitor’s ability to hold an electric charge between its two plates. 

The measurement of capacitance is called that of the farads (F)(abbreviated in F), named in honour of the British scientist Michael Faraday.

Capacitance is defined as having the capacitance of one farads (F) when one Coulomb can be stored in the plate with one volt of voltage. 

It is important to note that capacitance C is always positive and does not have negative units. 

However, farads (F) is a huge measurement unit to utilize as a stand-alone unit, so different sub-multiples of farads (F) are commonly used, like nano-farads and picofarads, Micro farads.


Types Of Capacitor

Capacity is the proportion of the electric charges (Q) to current (V), which is the equation of expression follows.

C = Q/V


It is the charge of electricity of coulombs

C refers to the capacitor of  farads (F)

V refers to the current voltage that exists between the plates in the volts.

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Dielectrics of Capacitor

Along with the overall dimension of the plates that conduct electricity and their distances or spacing. 

A different aspect that affects capacitance overall in the system is the kind of dielectric material employed. 

The conductive plates in capacitors are usually composed of a metallic foil or metal film, which allows the flow of electrons and charges; however, the dielectric material is always insulation. 

The different insulating materials employed as the dielectric of a capacitor differ in their capacity to block or transmit the electrical charge.

The dielectric material is composed of various insulating substances or mixtures of these materials. The most commonly used types include paper, air polypropylene, polyester Mylar glass, ceramics oil, or several different materials.

A dielectric material, also known as an insulator, enhances its capacitance capacitor compared to air is called dielectric constant, k. 

The dielectric material with an extremely high dielectric constant is an excellent insulation material than one with a lower dielectric constant. The dielectric constant is a non-dimensional value since it’s relative to the free space.

Applications of Paper Capacitors:

  • These capacitors are utilized for noise reduction as well as coupling and decoupling systems.
  • They can also be used to block DC signals to ensure that AC signals can be passed through.
  • Sensors like sensors for humidity as well as fuel level sensors etc . used capacitors made of paper.
  • Paper capacitors are utilized in-car audio systems since they supply extra power to amplifiers.