Capacitor: What Is It And What Do You Use It For?

by Joost Nusselder | Updated on:  May 26, 2022

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A capacitor is an electronic component that is used to store electrical energy.

Capacitors are made of two metal plates separated by an insulator, usually a dielectric, and can store a charge for a period of time.

They are used in a wide variety of electronic circuits and can be used to filter or store energy and can also be used to build simple oscillator circuits.

In this article, we will discuss what a capacitor is, what it is used for, and how it works.

Capacitor What Is It And What Do You Use It For(fw0d)

What is a capacitor?

A capacitor is an electrical component that stores energy in the form of an electric charge. It consists of two conductive plates contained within a dielectric material (insulating material). When connected to a power source, the plates become charged and electrical energy is stored in the dielectric material. This stored energy can then be released when needed, allowing it to be used for any number of applications.

Capacitors come in many shapes, sizes and materials – all depending on their purpose. The most common type of capacitor is known as a film capacitor – this uses thin layers of plastic or ceramic as the dielectric material, with thin conductive metal strips known as ‘electrodes’ on either side. These types of capacitors are widely used in electronics due to their low cost and durable properties.

Capacitors are also used in other applications such as motors and power supplies where they help regulate voltage or filter out noise and interference which can cause erratic performance or damage components down the line. As electronics become increasingly more complex, capacitors play an even more important role within these systems; helping maintain precise current flows during switching operations or providing buffering against sudden changes in voltage levels from external sources.

Types of capacitors

Capacitors come in a number of types, sizes and styles. Some capacitors are used in high-end audio systems while others are used in computers or home security systems. They all serve the same basic purpose; they store electrical energy when current is released and return that energy when the current stops. Types include the following:

Ceramic Capacitors: These are typically small and come pre-soldered onto circuit boards. They have a dielectric made from ceramic material and are usually used for low-level electronics, such as radio frequency interference (RFI) filters or bypass circuits.

Electrolytic Capacitors: These are commonly referred to as polarized capacitors because they have a negative anode terminal, a positive cathode terminal and electrolyte solution inside the capacitor body that allows for greater capacitor capacity. They’re typically found in power supplies, filters, timing circuits and many other points of power regulation.

Tantalum Capacitors: Made from tantalum oxide, these capacitors use a solid state dielectric (rather than liquid electrolyte). This gives them better temperature performance when compared to electrolytic capacitors, as well as improved stability over time and better consistency between batch products.

Film/Paper Capacitor: This type is constructed with metallized film or paper that acts as an insulator between two aluminum foil plates creating high surface area electrodes so it can store more electric charge. Commonly used where tolerance to electrical disturbances is required due to their ability to withstand surge currents caused by arcing or spark overvoltage conditions.

Supercapacitor/ Ultracapacitor: Also known as supercap/ ultra cap or electrochemical double-layer capacitor (EDLC), this type has very large storage capacities (generally higher than many other types) with improved endurance (up to hundreds of thousands of cycles). It’s designed for those applications requiring large amounts of energy on demand such as backup situation for data centers where seconds count before someone can manually switch on another power source.

Uses of a Capacitor

Capacitors are a basic electrical component that plays an important role in a variety of applications. They are commonly used to store electrical energy, create filters and in timing circuits. They are also used in car audio systems as well as consumer electronics. Let’s look at some of the uses of a capacitor in more detail.

Power supply smoothing

Capacitors can be used to provide filtering in a power supply circuit and help to create a smoother DC voltage. This is often seen in circuits that use mains power supplies, where rectification turns the AC into pulsed DC. An electrolytic capacitor is normally connected across the output of the rectifier as a smoothing element for the power supply. The capacitor charges quickly, holding some of its charge so that it helps smooth out any pulses from the rectifier and provides a more stable voltage to feed other components. The higher the capacitance, or storage capacity, in a capacitor, the more smoothing effect there will be as it can absorb more energy before requiring recharging. In this application, higher value capacitors reduce fluctuations, such as ripples in voltage levels and voltage spikes caused by load changes, providing stability to further elements within an application’s circuit.

Signal processing

Capacitors are widely used in signal processing and electronic communication. They are essential components in most electronic circuits, due to their ability to store and release energy.

In signal processing, capacitors can be used for their ability to reduce noise and filter out unwanted frequencies or signals. The protection of signals from noise is called smoothing or low-pass filtering, and is generally achieved through the use of capacitors.

In electronic communication, a capacitor can be used to transform an electrical signal from one form to another without changing its frequency. This process is known as coupling or voltage transfer, and capacitors are also commonly used for this purpose in radio receivers and transmitters. Additionally, capacitors act as part of high pass filters, which remove low-frequency signals while passing higher ones along the pathway.

Capacitors are also often employed in active analog filters: they determine the frequency response of a filter by setting its cutoff frequency. As such, they play a crucial role in controlling audio signals when designing music equipment such as amplifiers or mixing consoles.


Timing is a common use of capacitors. In everyday circuits, resistors are usually used for timing. However, in high-voltage or high-frequency situations, capacitors can often be used instead. It is often advantageous to use capacitors for timing because they do not dissipate power as quickly as resistors and can handle higher voltages with less risk of breakdowns.

In addition to providing a safe and efficient way of controlling voltage and current in a circuit, capacitors are also used to provide power at certain data points for components such as LEDs or transistors that may need pulses of current when activated. This can help strengthen the signal sent by the component so that it travels further without losing energy or integrity.

Capacitors are also used extensively in audio equipment to filter out signals and reduce distortion while still allowing useful information though with minimum noise interference. As mentioned earlier, they are also commonly placed across speaker terminals to help limit accidental short circuits while also maintaining an even load distribution on the amplifier output stages.

When used creatively and with understanding of electricity, capacitors have an amazing capacity to shape charge flow – allowing engineers to develop incredibly complex audio systems at minimal cost.

Common Applications

Capacitors are electrical components commonly used in a variety of applications. Their ability to store energy make them essential components of systems requiring a steady supply of energy over a period of time. They are used in many applications including power supplies, motors, audio systems, HVAC systems and more. In this article, we’ll explore some of the most common capacitor applications.


Motors use capacitors to control the speed of the motor or improve the start up torque. This is done by providing or removing a phase to the electric motor windings. Used in variable frequency drives, power supplies and other applications, capacitors can adjust voltage or current in pulsed loads and prevent energy from being wasted by dissipating unwanted energy from power systems. In currents under medium frequency motors, large capacitor values are usually used at both ends of the motor for running phase compensation capacitor banks to alleviate the harmonic effect of current waves caused by a converter’s non-linear load


Capacitors can be used to power and regulate lighting systems of all sizes. In electronic ballasts, they are used to control current flow and speed up the start-up process for fluorescent lights and high intensity discharge lighting. They also help to reduce flickering of lights. In transistorized circuit systems, capacitors maintain a continuous electrical current, helping to ensure that the lights stay lit. Additionally, they offer protection during voltage surges by reducing the electrical load on lighting fixtures in both indoor and outdoor settings.


Automotive capacitors are especially important because they are responsible for helping a vehicle’s electrical system reduce and compensate for inconsistencies in the flow of electricity, which is common in many vehicles. Automotive capacitors store energy to provide power to the car’s alternator or starter motor when needed. This energy is used to neutralize voltage spikes created when current demand exceeds the capacity of the battery or alternator. Automotive capacitors may also be used in audio systems, controlling currents within amplifiers and speakers. By smoothing out voltage fluctuations, automotive capacitors help prolong battery life and reduce strain on other electrical components.

Capacitor Safety

Safety should always be a top priority when working with a capacitor. Capacitors store energy and need to be handled with care while being charged or discharged. In this section, we will go over the safety guidelines to use when working with a capacitor and discuss potential risks associated with it.

Avoiding shorts

When using capacitors, it’s important to keep in mind the potential for shorts because of the fact that they are electrical components. Shorts occur when a capacitor short-circuits itself. While shorts can be caused by manufacturing defects or other external factors, most shorts are caused by improper use of capacitors.

To avoid shorts, you must always take precautions with capacitors. The following methods will help you maintain capacitor safety:

1) Never subject capacitors to excess stress or strain by overcharging them;
2) Do not leave capacitors in an overloaded state forlong periods of time;
3) Always use appropriate mounting techniques and/or methods that ensure shock isolation;
4) Do not connect two different polarities together as this could cause arcing and potentially damage the capacitor;
5) Inspect qualified components or materials (such as insulation materials) to ensure that there are no defects before installation;
6) Pay close attention to loading requirements -enforce reduced loading when possible and enforced adequate mounting techniques for all components; and
7) Be aware that standby voltages will cause a current flow throughout the circuit, which could potentially damage capacitor standard ratings if left unchecked.

By taking these precautions, users can help maintain safe usage and prevent dangerous situations from occurring due to short circuits or other issues with their capacitors. It’s important to remember that safety is always a top priority whenever working with electronics and especially with anything involving electricity!

Discharging capacitors

It is very important to ensure that capacitors are discharged properly when handling or replacing them. To perform a safe discharge, connect a resistor of 1k ohm to 10k ohm between each terminal of the capacitor and ground. The voltage across the capacitor will quickly dissipate without arcing or generating sparks, allowing for safe replacement or handling.

You must also remember to discharge high-voltage capacitors properly before disposal. If you do not discharge these components safely, they can pose an electrical hazard and even start a fire! Discharging these components involves hooking up an insulated wire between two terminals on the component and then discharging it over several minutes. Be sure to wear safety goggles while conducting this procedure in order to protect your eyes from sparks generated during the discharge process.

Disposing of capacitors

When disposing of capacitors, it is important to take the proper precautions for both safety and environmental protection. Because capacitors may contain possible toxins, such as lead, barium and other metals, you should avoid dumping these items in regular garbage bins or landfills. Instead they should be disposed of in an eco-friendly way by finding a suitable recycling collection center or a supplier that specializes in hazardous materials disposal.

It is important to ensure all capacitors still hold a charge before disposal – even if they are labeled as “dead” capacitors. Capacitors can retain residual charges and may discharge when handled; therefore you must use caution when handling them until you have discharge them. To safely discharge the capacitor, you will need an insulated screwdriver long enough to keep your hand back from the terminals so that the voltage does not arc jump your grip. Once charged capacitors have been discharged, remove any loose insulation with pliers or wire cutters and then wrap around insulators before disposing of them properly.


In conclusion, capacitors are essential components in any electrical circuit. They are used to store energy, to filter out noise and to provide a current source for AC circuits. Capacitors come in a variety of forms and have a broad range of applications. Understanding the basics of capacitors will help you identify the right components for your project.

Summary of capacitor basics

To summarize capacitor basics, a capacitor is an electrical component made up of two conducting plates separated by an insulating material called the dielectric. It is used to store energy in the form of an electric field. Capacitors are commonly used in electronic circuits, usually in conjunction with resistors and integrated circuits like microprocessors, to regulate current and voltage levels. They can also be used to filter signals and provide maximum power transfer in certain circuits. When selecting a capacitor for your specific application, it is important to consider the operating voltage, operating temperature, package size, and capacitance value range of the capacitor type you choose.

Benefits of using capacitors

Capacitors can be used in a variety of applications due to their ability to store energy and release it when needed. They are also capable of handling large amounts of current, so they are often used as filters and circuit brakes. Furthermore, capacitors can help reduce electrical noise and boost efficiency in power circuits. As a result, they are widely used in high power electronic devices such as computers, mobile phones, and television sets.

Capacitors have a number of benefits when it comes to electronics. For instance, they help keep the voltage level stable by providing temporary storage for high-energy pulses or short bursts of current that can otherwise damage electronics components over time. Their design also helps filter electromagnetic interference (EMI) throughout the system or within an individual circuit. This is important for preventing unwanted signals from entering the system or disrupting signals already within it.

In addition, capacitors provide instantaneous current when needed can reduce power consumption dramatically in any AC powered system by enabling start capacitor control and synchronous motor operation – which is critical for long-term operation in extreme environment applications like street lighting systems and HVAC motors. Finally, stablizing sine waves created by AC circuits is one of their primary functions — they pull energy out at certain frequencies while amplifying energy at other frequencies — reducing voltage distortion and ensuring clean power management across all channels.

I'm Joost Nusselder, the founder of Neaera and a content marketer, dad, and love trying out new equipment with guitar at the heart of my passion, and together with my team, I've been creating in-depth blog articles since 2020 to help loyal readers with recording and guitar tips.

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