Capacitors Definition

Capacitors are passive electrical components found in almost all electronics applications. Our range includes over 60,000 different capacitors including aluminium, tantalum, polymer, polyester film and ceramic capacitors. We source from globally renowned manufacturers AVX, Murata, KEMET, Panasonic, TDK and many more, so that you can rely on performance.

What is a Capacitor

Capacitors are fundamental electrical components found in nearly all electronics. We offer a wide variety of over 60,000 capacitors, including aluminium, tantalum, polymer, polyester film, and ceramic types. Our capacitors come from top manufacturers like AVX, Murata, KEMET, Panasonic, TDK, and more, ensuring reliable performance.

How Does A Capacitor Do?

Capacitors are essential electrical components found in almost all electronics. We offer a huge selection of over 60,000 capacitors, including aluminium, tantalum, polymer, polyester film, and ceramic types. These come from top manufacturers like AVX, Murata, KEMET, Panasonic, TDK, and more, so you can count on their performance.

I’ve just described what capacitors are. Now, let’s look at how a capacitor works. Electric current is the flow of electric charge that components use to power up, spin, or perform other functions. When current flows into a capacitor, the charges can’t pass through the insulating dielectric, so they get “trapped” on the plates. Electrons, which are negatively charged, gather on one plate, making it negatively charged overall. This causes the opposite plate to become positively charged due to the repulsion of similar charges.

Since opposite charges attract, the positive and negative charges on each plate pull towards each other. However, no matter how much they want to come together, the charges stay trapped on the plates because of the dielectric (unless they find another path). The electric field created by these stationary charges affects the electric potential energy and voltage. Just like a battery stores chemical energy, a capacitor stores electric energy when charges build up on its plates.

Types of Capacitors

Capacitors come in many shapes and sizes to fit different applications and needs. Here are some of the most common and important types of capacitors:

Ceramic Capacitors

Capacitors are used in high-frequency circuits, like those in audio and RF applications. For audio circuits, they are perfect for high-frequency correction. Sometimes these are called disc capacitors. Multilayer Ceramic Capacitors are made by coating both sides of a small ceramic disc with silver and stacking them together. Monolithic Ceramic capacitors can be made with different capacitance levels by adjusting the thickness of the ceramic disc.

Their values can range from a few picofarads to one microfarad, and they can handle voltages from a few volts up to several thousand volts. 100nF Ceramic Capacitors are inexpensive to produce and come in various dielectric types. Though ceramics don’t tolerate wear and tear very well, they perform their job effectively.

Electrolytic Capacitor

The most commonly used capacitors with a wide tolerance are electrolytic capacitors. They can handle working voltages up to about 500V, though the highest capacitance values aren’t available at such high voltages. Higher temperature units are available but are rare. The two most common types of electrolytic capacitors are tantalum and aluminum.

Tantalum capacitors

Tantalum capacitors offer better performance, higher values, and are available in a limited range of parameters. Tantalum oxide has much better dielectric properties than aluminum oxide, which means it has lower leakage current and higher capacitance, making it great for applications like obstructing, decoupling, and filtering.

The capacitance values of tantalum capacitors are very high for their size due to the thickness of the aluminum oxide coating and their higher breakdown voltage. A DC current anodizes the foil plates in a capacitor, setting the material’s limits and confirming the polarity of its sides. There are three main types of electrolytic capacitors: Aluminum Electrolytic Capacitors, Tantalum Electrolytic Capacitors, and Niobium Oxide Capacitors.

Film Capacitor

Film Capacitors are among the most commonly used types of capacitors and come in many varieties, mainly differing in their dielectric properties. They’re available in a wide range of sizes and can handle voltages up to 1500 volts. You can find them with tolerances ranging from 10% down to 0.1%. They also come in various shapes and housing types.

Film Capacitors are generally divided into two types: radial lead type and axial lead type. They have metalized aluminum or zinc electrodes applied to one or both sides of the plastic film, which gives them their metal film capacitor designation.

Because their dielectrics are made from materials like polystyrene, polycarbonate, or Teflon, film capacitors are sometimes called plastic capacitors. These types require a thicker dielectric film to minimize the risk of tears or punctures, making them better suited for lower capacitance values and larger case sizes.

While film capacitors are physically larger and more expensive, they are not polarized, so they can be used with AC power. Their electrical properties are much more stable. Depending on the capacitance and dissipation factor, they can replace Class 1 ceramic capacitors in applications that need stable frequency performance.

Applications of Capacitors

Capacitors are used in both electrical and electronic applications. They’re found in signal processing devices, filters, motor starters, and energy storage systems.

Frequently Asked Question

What happens if a capacitor fails?

If a capacitor fails, the circuit can become open, meaning it won’t start until some external force is applied. It’s possible for a bad (open) run capacitor to cause the current to be out of phase with the voltage.

What does an AC capacitor do?

An AC capacitor is part of the outdoor unit of an air conditioner or heat pump. It provides power to the motor that drives the cooling system. Basically, it gives the system an initial burst of energy to get it started when the cooling cycle begins.

Can a ceiling fan work without a capacitor?

A ceiling fan uses a single-phase capacitor run hub induction motor. If you provide a single-phase supply to a ceiling fan or any single-phase induction motor, it won’t rotate because there’s no starting torque.

Can I replace a capacitor with a higher UF in a ceiling fan?

You need to match the UF rating of the capacitor you’re replacing. The VAC rating of the new capacitor should be equal to or higher than the one you’re replacing.