Capacitors. Capacitor in AC Line

A capacitor is an electronic component that stores and releases electrical energy in a circuit. It consists of two conductive plates separated by an insulating material called a dielectric.

When voltage is applied across the plates, an electric field develops, causing positive charge to accumulate on one plate and negative charge on the other. This stored energy can then be released when the circuit requires it.

Key characteristics of capacitors include:

1. Capacitance: Measured in farads (F), it indicates the capacitor's ability to store charge. Common subunits are microfarads (μF), nanofarads (nF), and picofarads (pF).

2. Voltage Rating: The maximum voltage a capacitor can handle before breaking down.

3. Dielectric Material: Determines the capacitor's characteristics and performance, such as ceramic, electrolytic, tantalum, or film.

Capacitors are used in various applications, including:

• Energy Storage: Temporarily storing electrical energy in power supplies.
• Filtering: Smoothing out voltage fluctuations in power supplies and signal processing.
• Tuning Circuits: In radio frequency (RF) circuits to select desired frequencies.
• Timing Applications: In combination with resistors to create time delays.

Capacitors are crucial components in modern electronics, essential for energy storage, signal processing, and various other functions.

The capacity of a capacitor is measured in farads. A capacitor has a capacity of 1 farad when a charge of 1 coulomb increases the potential, between its plates, by 1 volt.

The capacity depends on four things: a) the higher the voltage used to charge the capacitor the more energy it will store; b) the larger the sizes of plates and the greater their number the more energy will be stored; c) the closer are the positive and negative plates the greater is the charge; d) some insulators store greater charge than others.

Capacitor in AC Line

When a capacitor is connected into a circuit through which alternating current is flowing, the plates of the capacitor are charged negatively or positively.

In order to show the action of a capacitor, in an AC line, connect a capacitor in series with a lamp and plug into the AC lighting. The lamp will glow provided its resistance does not prevent. Then connect another capacitor in parallel and the lamp will glow brighter. 

Connecting more capacitors and increasing the capacity we increase the glow. Thus, capacitors oppose the flow of current.