Magical Element

capacitor-
   A capacitor (originally known as a condenser) is a passive two-terminal electrical component used to store electricalenergy temporarily in the form  electrostatic field .The forms of practical capacitors vary widely, but all contain at least two electrical conductors (plates) separated by a dielectric (i.e. an insulator that can store energy by becoming polarized). The conductors can be thin films, foils or sintered beads of metal or conductive electrolyte, etc. The nonconducting dielectric acts to increase the capacitor's charge capacity. Materials commonly used as dielectrics include glass,ceramic, plastic film, air, vacuum, paper, mica, and oxide layers. Capacitors are widely used as parts of electrical circuits in many common electrical devices. Unlike a resistor, an ideal capacitor does not dissipate energy. Instead, a capacitor stores energy in the form of an electrostatic field between its plates.

An ideal capacitor is characterized by a single constant value, its capacitance. Capacitance is defined as the ratio of the electric charge Q on each conductor to the potential difference V between them. The SI unit of capacitance is the farad(F), which is equal to one coulomb per volt (1 C/V). Typical capacitance values range from about 1 pF (10⁻¹² F) to about 1 mF (10⁻³ F).

                               An ideal capacitor is wholly characterized by a constant capacitance C, defined as the ratio of charge ±Q on each conductor to the voltage V between them:^[13]

                                             

                                                            farads

Energy of electric field

Work must be done by an external influence to "move" charge between the conductors in a capacitor. When the external influence is removed, the charge separation persists in the electric field and energy is stored to be released when the charge is allowed to return to its equilibrium position. The work done in establishing the electric field, and hence the amount of energy stored, is

${\displaystyle W=\int _{0}^{Q}V(q)\mathrm {d} q=\int _{0}^{Q}{\frac {q}{C}}\mathrm {d} q={1 \over 2}{Q^{2} \over C}={1 \over 2}CV^{2}={1 \over 2}VQ}$

  

Dielectric

A dielectric material (dielectric for short) is an electrical insulator that can be polarized by an applied electric field. When a dielectric is placed in an electric field, electric charges do not flow through the material as they do in a conductor, but only slightly shift from their average equilibrium positions causing dielectric polarization. Because of dielectric polarization, positive charges are displaced toward the field and negative charges shift in the opposite direction. This creates an internal electric field that reduces the overall field within the dielectric itself.^[1] If a dielectric is composed of weakly bonded molecules, those molecules not only become polarized, but also reorient so that their symmetry axes align to the field.

The study of dielectric properties concerns storage and dissipation of electric and magnetic energy in materials. Dielectrics are important for explaining various phenomena in electronics, optics, and solid-state physics.

When a battery is connected to a series resistor and capacitor, the initial current is high as the battery transports charge from one plate of the capacitor to the other. The charging current asymptotically approaches zero as the capacitor becomes charged up to the battery voltage. Charging the capacitor stores energy in the electric field between the capacitor plates. The rate of charging is typically described in terms of a time constant RC.

 Here are some of the various types of capacitors and how they are used.

• Air - Often used in radio tuning circuits
• Mylar - Most commonly used for timer circuits like clocks, alarms and counters
• Glass - Good for high voltage applications
• Ceramic - Used for high frequency purposes like antennas, X-ray and MRI machines
• Super capacitor - Powers electric and hybrid cars