Capacitors are used in energy-storing devices such as TVs, radios, and other kinds of electronic equipment

Capacitors are small devices used to store electric charges
and consist of one or more pairs of conductors separated by an insulator. They’re
mainly used in energy-storing devices such as televisions, radios, and other
kinds of electronic equipment — basically, they’re everywhere in our daily
lives. When you tune a radio into a station, take a flash photo with a digital
camera, or change the channel on your HDTV, you’re making use of capacitors. Here
are 14 facts on this everyday technology. 

Capacitors

A collection of capacitors. Image source: Wikipedia.

  • A capacitor is a circuit component made of two
    conducting surfaces (plates) separated by a dielectric (non-conducting
    insulator) material.
  • Capacitor shapes are either flat or rolled
    (cylinder).
  • The Leyden jar was the first capacitor created,
    invented in 1945 by Pieter van Musschenbroek.
  • A capacitor’s conducting surfaces are made of
    different materials, including a thin film of conductive metal or aluminum.
  • The negatively charged plated is known as the cathode and the
    positively charged plate is known as the anode.
  • Capacitors with higher capacitance values are made
    from materials with a higher dielectric constant.
  • Dielectric materials used in capacitors include ceramic, air,
    vacuum, paper impregnated with oil or wax, mylar, polystyrene, mica, and glass.
  • When a capacitor is connected to a power source,
    positive charges transfer to one of the conducting surfaces, and negative
    charges are transferred to the other conducting surface.
  • A capacitor can absorb energy from a circuit and store it
    temporarily. The capacitor can then later return the energy to the
    circuit.
  • Capacitors discharge very slowly, but many can store a charge for
    years.
  • Handling a charged capacitor in the wrong way can result in
    burns or even death, especially if the capacitor is large.
  • A capacitor is discharged slowly when a resistor is
    connected to each leg. The resistor must be rated for the same or higher
    voltage than the capacitor can store for this method of discharge in order to
    work safely.
  • Capacitors are measured in a unit called farads, named after the
    scientists Michael Faraday. This measure is also known as capacitance.
  • Supercapacitors made with graphene as the conducting plate are
    capable of storing a charge similar to lithium-ion batteries.