How Capacitors Are Used in Electronic Circuits

How Capacitors Are Used in Electronic Circuits

Capacitors play a key role in enabling innovative electronic advancements that impact the world around us. Keeping up with the latest capacitor technologies, applications and best practices helps engineers and designers unlock the full potential of these vital components in their circuits.

In a capacitor, two conductive plates are separated by an insulating material known as a dielectric. The insulator, which can be made of plastic, ceramic or even air, prevents direct flow of current between the two plates. However, it allows an electric field to form across the plate. This field causes electrons to accumulate on one plate, while the other becomes positively charged. This separation of charges creates a stored electrical energy which can be released when the voltage across the capacitor changes.

When a DC voltage is applied to the capacitor, positive electrons begin to build up on one plate and negative electrons build up on the other plate. Eventually, for every electron that arrives at the negative plate, it is repelled by an equal number of electrons from the positive plate. This leaves the negative plate with an accumulation of electrons which can be used to store electricity.

The more electrons that accumulate on each plate, the greater the charge and hence the capacitance of the capacitor in farads (F). The capacitance is also increased by increasing the surface area of the plates or the distance between them. In addition, the insulating materials used in capacitors have different dielectric constants which can increase or decrease the capacity by a factor of k.

In contrast to batteries, capacitors do not have a finite amount of energy they can store. Once a certain level of negativity has built up on one plate, the plates will repel any new electronics trying to join them. The negative charge on the plates will then be so strong that it overcomes the electrostatic force of the electrons attempting to join them. This is what makes capacitors unique compared to batteries and other sources of electrical energy.

As the electrons on the plates of a capacitor are attracted to each other and repel them away from each other, they generate heat. This heat can cause a failure of the capacitor, so it is important that engineers select capacitors with the appropriate operating temperature and voltage ratings for their circuits.

In addition to ensuring that the voltages and other specifications of capacitors are compatible with their circuits, it is also necessary to consider other factors such as environmental conditions, cost and long-term reliability when selecting capacitors. Ultimately, the right capacitor selections will allow engineers and designers to unlock the full potential of this important component in their electronic devices and help shape a better future for humanity.