Capacitance is a measure of a capacitor’s ability to store electrical charge when a voltage difference exists between its plates. It is defined as the ratio of the magnitude of the charge on one of the plates to the voltage across the plates. Capacitance is indicated by the symbol C and is measured in Farads (F). One Farad is equal to one coulomb of stored charge per volt of potential difference between the plates. The capacitance depends on factors such as the surface area of the plates, the distance between them (dielectric thickness), and the permittivity of the dielectric material between the plates.
Capacitance is the property of a capacitor to store electrical energy in an electric field when a voltage difference exists between its conductors. A capacitor is usually made of two conductive plates separated by an insulating material known as a dielectric. When a voltage is applied across the plates, the electric charge builds up on the plates, creating an electric field between them. The amount of charge stored per unit of voltage is defined as the capacitance of the capacitor. Capacitors are used in electronic circuits for energy storage, power conditioning, filtering, signal coupling, and many other applications where capacitance properties are essential.
A capacitor is an electronic component that consists of two conductive plates separated by an insulating material called a dielectric. The conductive plates can be made of materials like aluminum, tantalum, or ceramic, while the dielectric material can be air, paper, plastic, or other non-conductive substances. Capacitors are designed to temporarily store electrical energy in an electric field. When a voltage is applied across the plates, opposite charges build up on each plate, creating an electric field between them. Capacitors are widely used in electronic circuits to stabilize voltage, filter noise, block DC while allowing AC signals to pass, and provide timing functions.
The SI unit of capacitance is the Farad (F), named after the physicist Michael Faraday. A Farad is defined as the capacitance of a capacitor that stores one coulomb of charge when a potential difference of one volt exists across its plates. In practical electronic applications, capacitance values are often expressed in microfarades (µF), nanofarades (NF), or picofarades (PF), which are smaller units of capacitance used to describe typical capacitor values encountered in the circuits.
Fixed capacitors are types of capacitors whose capacitance value is predetermined and cannot be adjusted or varied. There are several types of fixed capacitors used in electronics:
- Ceramic Capacitors: These capacitors use ceramic materials as the dielectric between the plates. They are widely used due to their small size, stability and low cost.
- Electrolytic capacitors: These capacitors have a liquid electrolyte (usually a conductive solution or gel) as their dielectric, and they are polarized, meaning they have a positive and negative terminal. Electrolytic capacitors offer high capacitance values in a compact size.
- Film Capacitors: Film capacitors use thin plastic film as the dielectric. They are known for their excellent stability, high reliability and good frequency characteristics. They are used in applications requiring precise capacitance values and low losses.
- Tantalum Capacitors: Tantalum capacitors use metal as one of the conductive plates and are known for their high capacitance per volume ratio. They are often used in compact electronic devices where space is limited.
- Mica capacitors: Mica capacitors use mica as a dielectric material. They are known for their high precision, stability and low losses at high frequencies. Mica capacitors are used in applications requiring high reliability and accuracy in capacitance values.
Each type of fixed capacitor has specific characteristics and advantages, making them suitable for different applications in electronic circuits based on factors such as size, capacitance value, voltage rating and frequency characteristics.