Capacitance

• Capacitor

  • Stores electric charge and energy
  • A capacitor consists conductors of two separated by an insulator.
  • Capacitors are energy-storing devices available in many sizes and shapes.
• In capacitors the conductors are called plates while the insulator is called dielectric
• The ability of a capacitor to store energy in the form of an electric charge is called its capacitance.
• Capacitor charge is the flow of electrons on to one plate and away from the other, resulting in a negative charge on one plate and a positive charge on the other.
• Capacitor discharge is the flow of electrons from the negatively charged plate of a capacitor to the positively charged plate eliminating the charge on the plate.
• The simplest type of capacitor consists of two parallel conducting plates separated by a thin sheet of material or dielectric.
• When a capacitor is connected to a battery (charging a capacitor), the battery supplies electric energy so that equal but opposite charges are placed on the capacitor plates.
• The plate connected to the battery’s negative terminal will receive a charge of–q. The plate connected to the battery’s positive terminal will receive a charge +q
• The amount of charge increases as the voltage increases.
• Capacitors are used in computer motherboards, electronic photoflash units, electric motors, automobile ignition units, fluorescent lamp starters and in television and radio circuits.
• A potential difference develops between the two plates; + plate is at higher potential. The work done to separate the charge ends up as electric potential energy. The stored potential energy is associated with this electric field.
• The total charge q that is transferred to each plate of the capacitor is proportional to the potential difference V across the plate.
• An increase of area will mean the capacitance of a capacitor will increase.
• Increase the distance between two points, will decrease the electric charge
• An increase of K (Dielectric) will mean the capacitance will increase, however the Voltage will decrease.
• In Electric diagram of a battery, the long side is positive while the shorter one is negative