The many wonders of capacitors

June 27, 2024 Luciano Bertene

Additionally, we will see how capacitors have revolutionized countless industries. Its influence is undeniable, from consumer electronics and automotive systems to renewable energy and medical devices. Capacitors are at the forefront of innovation, enabling advances in energy storage, power electronics and electronic control systems.

What is a capacitor?

Capacitance, commonly called a capacitor, is a simple passive device used to “store energy”. Capacitance is an element with the ability or “capacity” to store energy in the form of an infinite number of connected electrical charges that create a potential difference between plates, similar to a small and weak rechargeable battery.

There are many different types of capacitances, from very small capacitor spheres used in resonant circuits to huge power factor correction capacitors. However, they all have constant factors and storage rates.

Resistor color coding and resistance calculation

In its basic form, a capacitor consists of two or more parallel semiconductor (metallic) plates that are not connected or touching; however, they are electrically separated from each other by air or some type of good insulating material such as wax paper, mica, ceramic, plastic, or some type of liquid gel such as that used in electrolytic capacitors. The insulating coating between the capacitor plates is commonly called an insulator.

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Due to this insulating coating, direct current cannot flow through the capacitor because it blocks it, so that a voltage in the range of the associated electrical charges can exist between the plates.

The semiconductor metal plates of a capacitor may be square, circular, rectangular, or have a cylindrical or spherical shape, with the general shape, size, and construction of a parallel-plate capacitor depending on its application and voltage rating.

Resistance in the alternating current circuit

A capacitor will charge to its specified voltage when used in an instantaneous or direct current circuit. Still, it blocks the flow of current through it because the insulator of a capacitor is not a conductor and is essentially an insulator. However, once a capacitor is connected to an AC circuit, current flow appears to flow directly through the capacitor with very little or no resistance.

There are two types of electrical charge: charge in number of protons and electrical charge in number of electrons. When a DC voltage is applied to a capacitance, positive (+ve) charge rapidly accumulates on one plate while a corresponding negative (-ve) charge accumulates on the opposite plate. For every particle with a +ve charge that arrives at a plate, a charge of constant sign can depart from the -ve plate.

The plates then remain neutrally charged and a potential difference arises between the two plates, which is due to this charge. Once the capacitance reaches its steady state, the associated electrical current can no longer flow through the capacitance itself and around the circuit because the insulator separates the plates.

Types of resistors

The flow of electrons across the plates is understandable because the capacitor charging current flows until the voltage across each plate (and therefore across the capacitor) is equal to the applied voltage Vc. In this case, the capacitance is assumed to be “fully charged” with electrons. The magnitude or rate of this charging current peaks when the plates are fully discharged (initial state) and slowly decreases to zero as the plates are charged to a potential difference across the capacitor plates equal to the supply voltage.

The amount of electrical potential that exists above the capacitance depends on the proportion of charge that has been deposited on the plates by the work done by the source.

Conclusion

Furthermore, capacitors have transformed countless industries. They are an essential part of consumer electronics and enable smaller, more powerful devices. They are important components in renewable energy systems and facilitate energy storage and distribution. Capacitors play an important role in telecommunications, automotive systems, aerospace engineering, medical devices, etc.