Capacitance & Charge - How Capacitors Store & Release Energy |

12 Nov, 2019 | Quest Components
Capacitance And Charge

Capacitance and Charge

A capacitor is a component that has the ability to store an electrical charge. It is similar to, yet different from, a battery. Both capacitors and batteries store electrical energy, but they do so in different ways.

A capacitor stores energy in the form of an electric charge within an electromagnetic field. It is a useful part of an electrical circuit in that it can provide a buffer in case of an interruption in power.

What is a Charge?

When energy is trapped and held in an electromagnetic field, it is called a charge. A charge can be positive or negative. Atoms, the building blocks of all things, are made up of protons, neutrons, and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons are neutral as their name suggests. Positive and negative charges repel each other like the opposite ends of a magnet.

How Does a Capacitor Work?

Capacitors are made up of metal plates with a dielectric (non-conductive) material in between. Upon receiving a charge, one metal plate will be positive and the other negative, much like the opposite ends of a battery. The electrical energy is trapped within the electromagnetic field, storing a charge until the energy source is removed and the capacitor discharges all of its stored energy.

What is Capacitance?

Capacitance refers to the amount of energy a capacitor can store in its electromagnetic field. The capacitance of a specific capacitor depends on a variety of factors such as the design and makeup. There are fixed capacitors (capacitance is not adjustable) and variable capacitors (capacitance is adjustable).

How do Different Types of Capacitors Vary in Capacitance?

There are many different types of capacitors built with different materials. The type of material used as the dielectric, as well as the distance between the plates, determines its capacitance.

Here are some commonly used types of capacitors and their range of capacitance:

Fixed Capacitors (capacitance is finite, it cannot be changed)

Mica A capacitor containing mica (a naturally occurring element) as the dielectric typically have a relatively low capacitance, between a few pF up to a few nF. The largest mica capacitors may reach up to 1 µF. This model CD15ED330J03 is an example of a standard mica capacitor.

Ceramic A capacitor with a ceramic dielectric will typically have a capacitance between 1 nF and 1 µF. Ceramic capacitors are categorized into three classes. Class 1 ceramic capacitors provide high stability and low loss, such as this model: CC0402JRNPO9BN101. Class 1 capacitors are often referred to as NP0 or C0G. Class 2 ceramic capacitors, such as GRM155R71C104KA88D, have a higher capacitance per volume and are used in applications where accuracy is less important. Class 2 capacitors are often referred to as X7R or Z5U as their temperature coefficient value.

Film Using a plastic film (thin layer of plastic) that may or may not be metalized depending on the need, a film capacitor typically achieves a capacitance of between 1 nF and 30 µF. This model ECQV1H104JL is an example.

Electrolytic Using an electrolyte dielectric allows this capacitor to achieve a much larger capacitance than other types. Their capacitance ranges from 1 µF to 47 mF. An example of an electrolytic capacitor would be this model UVX1C220MDA.

Supercapacitors These are a type of electrolytic capacitor that are capable of achieving the highest capacitance, up to 12,000 F. They do so by combining the energy storage methods of capacitors and batteries, meaning they store some electricity electrostatically, and some electrochemically.

Array/Network Capacitors An array consists of a group of capacitors that are contained in one package but are not connected. This allows each capacitor to be added into or removed from the circuit as needed. A network is a group of capacitors packaged together and connected by a circuit.

Know your Capacitance Needs

If you have a good idea of the level of capacitance you need for your project it will be much easier to select the right products. At Quest Components knowledgeable representatives are available to assist you when you call. Simply explain your needs and be matched with the right products for the job.

Quest Components has an Extensive Inventory of Capacitors

Whatever type of capacitor you need, Quest Components has a variety of models to choose from. Call (623) 333-5858 today to inquire about Questcomp’s capacitor component availability.

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