# What Does a Capacitor Do?

If you’re new to the world of capacitors, then this comprehensive guide is for you! In this article, we will discuss the basics of what capacitors do, as well as some more advanced concepts. We’ll answer common questions like “What’s the point of a capacitor?” and “How do capacitors work?” Plus, we’ll give you some tips on how to select the right capacitor for your needs. So whether you’re just getting started in electronics or you’re looking to learn more about capacitors, read on!

## What is a Capacitor?

A capacitor works by storing an electrical charge in an electrostatic field. This process is known as capacitance, and it occurs when two conductive plates are separated by an insulating material, known as a dielectric.

When a voltage difference exists between the plates, an electric field is created in the dielectric. In addition to that, the dielectric also helps to prevent the flow of electrons and allows the capacitor to store a charge. This field stores energy and causes a current to flow through the capacitor. The current stops flowing when the voltage across the capacitor plates equals zero.

### How does a capacitor work?

A capacitor works by storing an electrical charge in an electrostatic field. This process is known as capacitance, and it occurs when two conductive plates are separated by an insulating material, known as a dielectric. When a voltage is applied to the plates, electrons flow from one plate to the other, creating an electric field between them. The dielectric helps to prevent the flow of electrons and allows the capacitor to store a charge.

Capacitors can be connected in series or in parallel to create different effects. When they are connected in series, the overall capacitance is reduced. This is because the electric field created by each capacitor opposes the fields of the other capacitors in the circuit. When capacitors are connected in parallel, the overall capacitance is increased. This is because the electric fields created by each capacitor add together to create a larger field.

### What is capacitance?

Capacitance is the ability of a device to store electrical energy in an electric field. It is measured in farads (F). The higher the capacitance, the more charge the capacitor can store. Capacitors are used in a wide range of electronic devices, including radios, televisions, computers, and portable electronics. [1], [2]

## History of Capacitors

A capacitor is a device that stores electrical energy in an electric field. It is a passive electronic component with two terminals. The effect of a capacitor is known as capacitance. While some capacitors are used for power conditioning, others are used in analog circuits such as filters or tuning circuits. Capacitors were first used in the 18th century by the Italian physicist Alessandro Volta, who called them “condensators”.

The invention of the primitive capacitor is generally credited to German engineer Otto von Guericke who, in 1672, devised a device that could store static charges upon rubbing it with a cloth. The earliest version of the capacitor consisted of a sulfur globe that could be charged with static electricity by rubbing it.

The creation was improved further in 1746, by two German physicists Ewald Georg von Kleist and Pieter van Musschenbroek. They discovered that when he charged a Leyden jar (a type of glass jar used to store electrical charges), it could discharge its charge through his body even though there was no physical connection between his body and the jar. This discovery led to the development of the electronic circuit and paved the way for the creation of the capacitor.

The studies on Leyden jar were continued by the American scientist, and of course the future president, Benjamin Franklin. In the 1740s and 1750s, he published several papers on his experiments and observations. One of his most famous findings was that the charge could be stored on the inner surface of the jar as well as on the outer surface. Daniel Gralath and Johann Heinrich also performed their own experiments which eventually led to the development of the first practical capacitor.

In 1800, the Italian physicist Alessandro Volta is credited with the invention of “condenser” (what we now know as capacitor). Volta discovered that when he stacked alternating layers of zinc and silver, he could create a device that could store electrical energy.

Electrolytic capacitor was invented in 1896 by the German engineer Karl Ferdinand Braun. It was the first capacitor that could store a large amount of electrical energy.

The modern aluminum electrolytic capacitor was invented in 1896 by the German inventor Karol Pollak.

In 1909, compact disc (CD) was invented by the German physicist Oskar Heil.

In 1910, the first air-gap capacitor was invented by the French engineer Georges Claude.

In 1931, the first plastic capacitor was invented by the American scientist William Dubilier. He used a mica dielectric as a ceramic dielectric to create a capacitor that could store a large amount of electrical energy.

The history of capacitors is full of important discoveries and inventions that have led to the development of the modern electronic circuit. The capacitor is a crucial component in many electronic devices, and its importance will continue to grow as we become increasingly reliant on electronics in our everyday lives. [1], [3]

## Types of Capacitors

Just like any other electronic component, capacitors come in a variety of shapes and sizes. The type of capacitor you need will depend on the application you are using it for. Below are some common types of capacitors.

### Ceramic capacitors

Ceramic capacitors are made from two layers of ceramic material with a metal electrode in between. They are small and lightweight, making them ideal for use in portable electronic devices. Ceramic capacitors also have a very high operating temperature, making them suitable for use in high-temperature applications.

Ceramic capacitors come in two main types: monolithic and multilayer. Monolithic ceramic capacitors are made from a single piece of ceramic material, while multilayer ceramic capacitors are made from multiple layers of ceramic material bonded together.

Multilayer ceramic capacitors are more common than monolithic ceramic capacitors because they offer higher levels of performance and reliability. However, monolithic ceramic capacitors are often used in applications where size and weight are critical, such as in portable electronic devices.

Ceramic capacitors are also classified according to their dielectric constant. The most common types of ceramic capacitor are Class II and Class III capacitors, which have dielectric constants of about 25 and 50, respectively.

Class I ceramic capacitors, which have a dielectric constant of around 100, are also available but are less common than Class II and Class III capacitors.

### Mylar capacitors

Mylar capacitors are made from two layers of mylar (a type of plastic) with a metal electrode in between. They are similar in construction to ceramic capacitors, but they have a lower operating temperature and are not as suitable for use in high-temperature applications.

### Film capacitors

Film capacitors are made by sandwiching a thin film of dielectric material between two metal plates. They are available in both cylindrical and flat packages. Film capacitors are used in applications where high frequency and stability are required, such as audio equipment and medical devices. Film capacitors are known to offer superior performance in terms of frequency response and stability.

### Glass capacitors

One of the earliest types of capacitors, glass capacitors were used in early radios. These capacitors are made of two metal plates that are separated by a thin layer of dielectric material. Dielectric can be a variety of materials, but most commonly it is a type of glass.

Glass capacitors are not used very often anymore because they are relatively large and have a relatively low maximum voltage rating. However, they do have one advantage over other capacitor types: they can withstand high temperatures without degradation.

If you need a capacitor that can handle high temperatures, then a glass capacitor might be the right choice for you.

### Electrolytic capacitors

This type of capacitor is made up of two metal plates that are separated by an electrolyte. When a voltage is applied to the plates, one of the plates will become positively charged and the other plate will become negatively charged. The electrolyte between the plates helps to keep the charges from leaking away.

Electrolytic capacitors are used in a variety of applications including power supplies, audio equipment, and computer motherboards.

### Air capacitors

Air capacitors are another type of capacitor. They consist of two metal plates separated by a dielectric material, in this case air. Air capacitors are used in applications where space is limited, such as in portable electronics.

One advantage of air capacitors is that they can be made very small. However, this also means that they have a relatively low capacitance. Another disadvantage of air capacitors is that the dielectric material (air) can be easily damaged, which reduces the capacitor’s lifespan. [4]

## Uses for Capacitors

Capacitors are used in a wide range of electronic circuits, including power supplies, filters, and timing circuits. They are also used in electrical energy storage applications, such as batteries and fuel cells. Capacitors can be found in almost every type of electronic device, from radios to laptops to cell phones.

### To store energy

As for the reasons why capacitors are used, it has to do with the capacitor’s ability to store an electric charge. This property is known as capacitance, and it is measured in units of Farads (symbol: F). The capacitance of a capacitor is determined by the size of its plates and the distance between them.

### For signal coupling

Another common use for capacitors is to couple two circuits together. This is done by connecting the capacitor between the two circuits. The capacitor will allow AC signals to pass from one circuit to the other, but will block DC signals. This is known as AC coupling.

Capacitors can also be used to decouple two circuits that are connected together. This is done by connecting the capacitor between the two circuits. The capacitor will block AC signals and allow DC signals to pass from one circuit to another.

### Electronic noise filtering

One of the most common uses for capacitors is to filter out unwanted electronic noise. This noise can come from a variety of sources, including power supplies, motors, and other electrical devices. Capacitors are able to filter out this noise because they can store and release electric charge very quickly.

### Remote sensing

Another common use for capacitors is in remote sensing applications. Capacitors can be used to measure a variety of environmental parameters, including temperature, humidity, and pressure.

In many cases, capacitors are used in conjunction with other sensors, such as thermocouples or strain gauges. By measuring the voltage across the capacitor, it is possible to determine the value of the parameter being measured.

Capacitors are also used in medical applications, such as cardiac pacemakers and defibrillators. In these devices, capacitors are used to store electrical energy that is later discharged into the patient’s body in order to correct a heart rhythm that has become too slow or too fast.

### To keep the voltage on the same level

One of the most common uses for capacitors is to maintain a voltage level. This can be done by charging the capacitor to the desired voltage and then connecting it in parallel with the circuit element whose voltage is to be regulated. The capacitor will then act as a reservoir of charge, supplying or absorbing charge as needed to keep the voltage at the desired level.

This use for capacitors is especially important in power supply circuits, where capacitors are used to filter out unwanted AC (alternating current) components from the DC (direct current) output of the power supply. By smoothing out these AC fluctuations, capacitors help to ensure that electronic devices receive a constant supply of power.

As you can see, there are a variety of different ways that capacitors can be used. By understanding what these components do, you can better understand how electronic devices work.

### To charge and discharge electric charges

Another common use for capacitors is to store electric charges. This can be useful in a number of applications, such as powering flashlights and other devices that need a quick burst of energy. Capacitors can also be used to filter out unwanted noise or signals in electronic circuits. [2]

## What is the Measurement Unit of Capacitors?

The size of a capacitor is usually indicated by its capacitance, which is measured in Farads (named after Michael Faraday). A Farad is a very large unit of capacitance, so most capacitors have values that are much smaller than one Farad. The most common units of capacitance are microfarads (µF) and picofarads (pF). One microfarad equals one millionth (0.000001) of a Farad, and one picofarad equals one trillionth (0.000000000001) of a Farad.

One farad has an ability to store one coulomb of charge at one volt. This means farab is a pretty big unit.

The capacitance of a capacitor is determined by its size, shape, and the type of material it is made from. The larger the plate area or the smaller the distance between the plates, the higher the capacitance. The dielectric constant of the material between the plates also affects capacitance. A higher dielectric constant means that more charge can be stored on the capacitor plates for a given voltage difference between them. [1], [2]

## Ratings of Capacitors

Capacitors have values other than capacitance, including voltage, tolerance and temperature ratings.

### Tolerance

The capacitance of a capacitor is the amount of charge that it can store. The tolerance of a capacitor is the range within which the capacitance can vary. The capacitance is usually given as a percentage, such as “+/- 20%”. This means that if the specified capacitance is 100 microfarads, the actual value of the capacitor can be anywhere between 80 and 120 microfarads.

The tolerance of a capacitor affects how well it will perform its intended function in a circuit. For example, if a capacitor is used to filter out AC ripple from DC power, then a higher tolerance (such as “+/- 20%”) will be needed to ensure that the ripple is significantly reduced. On the other hand, if a capacitor is used to tune a radio receiver, then a lower tolerance (such as “+/- 0.01%) will be needed to ensure that the receiver is tuned to the correct frequency.

### Voltage

The voltage that a capacitor can withstand before it breaks down is called its maximum voltage or breakdown voltage. The value of the maximum voltage depends on the type of material used in the capacitor’s electrodes and dielectric, as well as on the size and shape of the capacitor.

For example, a standard electrolytic capacitor can have a maximum voltage of about 35 volts. However, there are also high-voltage electrolytic capacitors that can have a maximum voltage of 1000 volts or more.

To find out the maximum voltage of a particular capacitor, you need to consult its datasheet. The datasheet will also specify the recommended operating voltage, which is usually much lower than the maximum voltage.

### Maximum working temperature

As with all electronic devices, capacitors have a maximum working temperature. This is the temperature at which the capacitor will no longer function correctly. The max working temp of a capacitor is usually around 125°C. However, some capacitors can have a max temp as high as 200°C.

When choosing a capacitor, it’s important to make sure that its max working temp is higher than the operating temperature of your circuit. If not, the capacitor could fail and cause your circuit to malfunction.

If you’re ever in doubt about what temperature range a particular capacitor can handle, you can always consult the datasheet for more information.

### Temperature coefficient

The temperature coefficient of a capacitor is a measure of how its capacitance changes with temperature. The lower the temperature coefficient, the more stable the capacitance of the capacitor will be over a range of temperatures.

There are two types of temperature coefficients: positive and negative. A positive temperature coefficient means that the capacitance of the capacitor increases as the temperature increases. A negative temperature coefficient means that the capacitance decreases as the temperature increases. Most ceramic and film capacitors have a negative temperature coefficient, while electrolytic capacitors have a positive temperature Coefficient.

### Leakage resistance

The capacitor’s leakage resistance is the measure of how much current flows through the capacitor when there is a voltage applied to it. The higher the leakage resistance, the less current that will flow.

### Self inductance

A capacitor has self inductance because it is made of two conducting plates separated by an insulator. This separation creates a magnetic field around the capacitor that opposes any change in current. The larger the plates and the greater the separation, the greater the self inductance.

The self inductance of a capacitor can be either positive or negative. A positive self inductance means that the magnetic field created by the current flowing through the capacitor opposes any increase in current. A negative self inductance means that the magnetic field actually aids any increase in current. Either way, the effect of self inductance is to oppose any change in current flow through the capacitor.

The magnitude of a capacitor’s self inductance is usually very small, on the order of nanohenries (nH). However, in some applications, such as radio frequency (RF) circuits, the self inductance can be a significant factor.

Self inductance is not the only factor that determines a capacitor’s behavior. You will really only start to see the effects of it on higher frequencies.

### Polarity

A capacitor has two plates that are separated by an insulator, also known as the dielectric. The dielectric helps to increase the capacitance of the device. When voltage is applied to the device, positive charges collect on one plate while negative charges collect on the other. This creates an electric field between the two plates.

The polarity of a capacitor is important because it determines the direction of current flow through the device. If you reverse the voltage across a capacitor, the current will flow in the opposite direction. This can be useful in certain types of circuits, but it’s important to be aware of the polarity of your capacitor before you connect it to a circuit.

Capacitors can be either polarized or non-polarized. Polarized capacitors have a positive and a negative lead, while non-polarized capacitors do not.

Polarized capacitors can only be connected to a circuit in the correct orientation. If you try to connect a polarized capacitor backwards, it will not work properly. In some cases, it may even be damaged.

Non-polarized capacitors, on the other hand, can be connected to a circuit in any orientation. This makes them much easier to use than polarized capacitors. [5]

## FAQ

### What is the purpose of a capacitor?

A capacitor’s purpose is to store energy in the form of an electrostatic field. This type of storage is known as “passive storage.” When a capacitor is connected to a circuit, it can hold a charge and then release that charge later on when needed.

### What three things does a capacitor do?

A capacitor has three main functions: it stores energy in the form of an electrostatic field, it can act as a voltage regulator by shunting current to ground, and it blocks DC while passing AC.

### What does a capacitor do and its importance?

A capacitor is an electrical component that stores energy in the form of an electric field. It is composed of two conducting plates (usually made of metal) separated by an insulating material called a dielectric. When a voltage is applied across the plates, the electric field stores energy in the form of an electrostatic charge. The amount of energy that can be stored in a capacitor is determined by its capacitance, which is measured in farads.

While capacitors are commonly used to store energy, they also have a number of other important applications. For example, they can be used to filter out unwanted signals in electronic circuits, or to smooth out power fluctuations caused by inductive loads.

### Why do motors need capacitors?

Capacitors help to supply the initial surge of current to the motor windings when it starts up. This surge is needed because motors have inductance, which opposes any changes in current flow. The capacitor’s job is to provide that initial surge so that the motor can start turning.

Once the motor is running, the capacitor acts as a filter, smoothing out any fluctuations in the current flowing to the windings. This helps to improve the efficiency of the motor and prevents damage from electrical shocks.