current

Cards (9)

  • current = charge / time
  • what is current?
    the rate of flow of charge, an electric current is carried by a flow of electrons
    electrons carry negative charge
    the amount of charge passing through a point in a circuit per unit time
  • what is the unit for current?
    'ampere' (A)
    1 ampere = 1 coulomb per second
  • current calculation 

    Q=I x t
    Q = charge/coulombs
    I = current/amps
    t = time/seconds
  • direct current 

    direct potential differences produce direct currents
    direct currents always flow in the same direction (polarity)
  • alternating current
    alternating potential differences produce alternating currents
    alternating currents change direction (polarity)
  • an ammeter measures current in amps
  • ammeters must be placed in series
  • the greater the resistance, the smaller the current that flows through it for a given potential difference across the component