Capacitors are like magic little storage boxes in the world of electronics. Though their operation might seem mysterious, with a little exploration, you can understand their core principles and uses.

Robot Tips Capacitors Farad How it works

23 August 2023 by Kevin McAleer | Share this article on

Capacitors are like magic little storage boxes in the world of electronics. Though their operation might seem mysterious, with a little exploration, you can understand their core principles and uses.

This guide will help demystify the world of capacitors for beginners.

How Do Capacitors Work?

At its core, a capacitor is a device that stores electrical energy in an electric field. When voltage (a difference in electric potential) is applied across the terminals of a capacitor, it stores energy by accumulating electric charges on its plates. These charges remain in the capacitor until they are discharged, either by being connected to a circuit or through natural leakage over time.

What Are Capacitors Made Of?

Capacitors consist of two conductive plates separated by an insulating material known as a dielectric. The dielectric can be made of various materials, including air, ceramic, mica, tantalum, and more. The nature of the dielectric, along with the surface area and distance between the plates, determines the capacitance value and other properties of the capacitor.

Different Types of Capacitors

There are various types of capacitors, each tailored for specific applications and characteristics:

  • Ceramic Capacitors: Made using ceramic material as the dielectric. They are non-polarized and are commonly used for general-purpose applications.

  • Electrolytic Capacitors: These are polarized, meaning they have a positive and a negative side. They typically have higher capacitance values and are used in power supply filtering and audio applications.

  • Tantalum Capacitors: Similar to electrolytic capacitors but use tantalum for the plates. They are more stable and reliable but also more expensive.

  • Film Capacitors: Made using a thin plastic film as the dielectric. They are non-polarized and are used in high-frequency applications.

  • Supercapacitors (or Ultracapacitors): These can store a large amount of energy compared to standard capacitors and can deliver it rapidly. They find applications in energy storage and rapid-charge/discharge systems.

Who Invented the Capacitor?

The earliest form of the capacitor was the Leyden jar, invented independently by Ewald Georg von Kleist and Pieter van Musschenbroek in 1745-46. Over the years, as our understanding of electricity expanded, the design and efficiency of capacitors have been greatly refined.

Units of Measure

The primary unit of capacitance is the Farad (F). However, a Farad is a large unit, so you’ll often see capacitors rated in microfarads (µF), nanofarads (nF), or picofarads (pF). The relation is:

1 F = 1,000,000 µF = 1,000,000,000 nF = 1,000,000,000,000 pF

Capacitors also have other ratings like voltage (maximum voltage the capacitor can handle) and tolerance (how close the actual capacitance is to the stated value).

Common Uses of Capacitors

Capacitors have a myriad of applications:

  • Filtering: In power supplies, capacitors help smooth out the voltage.

  • Tuning: Used in radios to select a particular frequency.

  • Timing: In conjunction with resistors, capacitors can create circuits that produce specific time delays.

  • Energy Storage: Supercapacitors store energy in applications like backup power.

  • Motor Start and Run: Help motors start and run efficiently.

  • Signal Processing: In audio and communication devices, capacitors are used for tasks like coupling and decoupling AC signals.


Capacitors are fundamental components in electronics, offering a wide range of functionalities from simple energy storage to complex signal processing. Understanding how they work and their diverse applications is a significant step in mastering electronics. Whether you’re just curious or diving deep into the realm of electronics, capacitors are sure to be a crucial part of your journey!

Kevin McAleer

I build robots, bring them to life with code, and have a whole load of fun along the way

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