capacitance

(redirected from Nominal capacity)
Also found in: Dictionary, Thesaurus, Medical.

capacitance,

in electricity, capability of a body, system, circuit, or device for storing electric charge. Capacitance is expressed as the ratio of stored charge in coulombs to the impressed potential difference in volts. The resulting unit of capacitance is the faradfarad
[for Michael Faraday], unit of electrical capacitance, equivalent to 1 coulomb of stored charge per volt of applied potential difference.
..... Click the link for more information.
 [for Michael FaradayFaraday, Michael
, 1791–1867, English scientist. The son of a blacksmith, he was apprenticed to a bookbinder at the age of 14. He had little formal education, but acquired a store of scientific knowledge through reading and by attending educational lectures including, in
..... Click the link for more information.
]. In an electric circuit the device designed to store charge is called a capacitorcapacitor
or condenser,
device for the storage of electric charge. Simple capacitors consist of two plates made of an electrically conducting material (e.g., a metal) and separated by a nonconducting material or dielectric (e.g.
..... Click the link for more information.
. An ideal capacitor, i.e., one having no resistance or inductance, may be spoken of as a capacitance. When an alternating current flows through a capacitor, the capacitor produces a reactance that resists the current (see impedanceimpedance,
in electricity, measure in ohms of the degree to which an electric circuit resists the flow of electric current when a voltage is impressed across its terminals.
..... Click the link for more information.
). While every element of a circuit has some capacitance, it is a goal of good design to reduce such unwanted or stray capacitance to a minimum.

Capacitance

The ratio of the charge q on one of the plates of a capacitor (there being an equal and opposite charge on the other plate) to the potential difference v between the plates; that is, capacitance (formerly called capacity) is C = q/v.

In general, a capacitor, often called a condenser, consists of two metal plates insulated from each other by a dielectric. The capacitance of a capacitor depends on the geometry of the plates and the kind of dielectric used, since these factors determine the charge which can be put on the plates by a unit potential difference existing between the plates.

In an ideal capacitor, no conduction current flows between the plates. A real capacitor of good quality is the circuit equivalent of an ideal capacitor with a very high resistance in parallel or, in alternating-current (ac) circuits, of an ideal capacitor with a low resistance in series. See Capacitor, Dielectric materials

Capacitance

 

a quantitative measure of a conductor’s ability to hold an electric charge. In an electrostatic field, all points of a conductor are at the same potential φ. If infinity is taken as the zero point for potential, φ is proportional to the charge q on the conductor; that is, the ratio of q to φ is not a function of q. The capacitance C of an isolated conductor is equal to the ratio of the charge on the conductor to the conductor’s potential: C = q/φ. Thus, the greater the capacitance, the greater the charge that can be stored by the conductor at a given φ.

Capacitance is determined by the size and shape of a conductor and by the electrical properties of the surrounding medium, that is, by the medium’s dielectric constant. Capacitance does not depend on the material of the conductor. Specifically, in the centimeter-gram-second (cgs) electrostatic system, the capacitance of a conducting sphere in vacuo is equal to the radius of the sphere. Since the potential of a conductor also depends on the electric fields created by the charges induced in the surrounding bodies as a result of electrostatic induction, the presence of bodies near a conductor changes its capacitance. Capacitance is measured in centimeters in the cgs system and in farads (1 farad = 9 × 1011 cm) in the International System of Units (SI).

The concept of capacitance applies not only to a single conductor but also to systems of conductors. It applies in particular to a system of two conductors that are separated by a thin dielectric layer. Such a system is called a capacitor. The capacitance of a capacitor is expressed by the equation C = q/(φ1 – φ2). where q is the charge on one plate, –q is the charge on the other plate, and φ1 – φ2 is the potential difference between the plates. The capacitance of a capacitor is virtually independent of the presence of surrounding bodies and can be very high in capacitors with small dimensions.

REFERENCE

Tamm, I. E. Osnovy teorii elektrichestva, 9th ed. Moscow, 1976. Chapter 1.
Kalashnikov, S. G. Elektrichestvo, 4th ed. (Obshchii kurs fiziki). Moscow, 1977.

G. IA. MIAKISHEV

capacitance

[kə′pas·ə·təns]
(electricity)
The ratio of the charge on one of the conductors of a capacitor (there being an equal and opposite charge on the other conductor) to the potential difference between the conductors. Symbolized C. Formerly known as capacity.
(engineering)
In a closed feedwater heater, the volume of water required for proper operation of the drain control valve.

capacitance

The quantitative measure of the electric-energy storage capability of a capacitor; usually measured in farads or microfarads (10-6 farads).

capacitance

1. Electronics the property of a system that enables it to store electric charge
2. a measure of this, equal to the charge that must be added to such a system to raise its electrical potential by one unit.

capacitance

The property of a capacitor or other device to hold a charge. It is measured in Farads (F). See Farad.
References in periodicals archive ?
The protocol for evaluating the nominal capacity of systems that cannot operate at 0% outside air, such as the certified WCC Type-1 Hybrid, is described in a later section.
Nominal capacity is 5000 lb/hr, but output is limited by the ability to cool the profile, depending on its formulation and design.
According to P+E, the modular system has a nominal capacity of 1,300 liters per minute and is capable of producing ultra-pure hydrogen (UPH), which contains less than one part per billion total impurities.
From a global company's advertorial: "Given the limitations on current storage management technology imposed by heterogeneous storage infrastructure, achieving nominal capacity allocation and utilization efficiency is nothing short of a black art.
The REFLEX M 16 has a nominal capacity of 1600kg and a maximum lift height of 8.
The refinery, operated by Venezuelan state oil company Petroleos de Venezuela (PDVSA), has a nominal capacity of 320,000 bpd began processing crude at 40,000 bpd a week earlier.
The unit with a nominal capacity of 30,000 metric tons per year will utilize a proprietary hydrogenation technology recently developed, based on metallocene (titanium) catalysts.
foundries installed Simplicity/Richards PX2500G gas-fired thermal reclamation systems with a nominal capacity of 2.
The 200 MW Los Vientos I windpower project consists of 87 Siemens wind turbines, each with a nominal capacity of 2.
Tenders are invited for Rmo 2X14 Tr 50Kw Capacity Precision Type Ac Units Installed In Micro Film Repository At Nai Annexe Building Janpath New Delhi Sh: Providing Comprehensive Maintenance Of 2 Nos 14 Tr 50Kw Nominal Capacity Precision Type Air Cooled Ac Units
He said that the power plant will joint the national grid with full nominal capacity in the next two to three days.
Sabine Liquefaction is developing six liquefaction trains, each with expected nominal capacity of 4.