Electric Circuts

• Variables

  • Potential difference
  • Electric current
• Potential difference

  Volts [V]
• Electric current

  Ampere [I]
• Resistance

  Ohm [R]
• Potential difference

  The difference in electrical potential between two points in an electric circuit
• Current


  The amount of electric charge transferred per unit of time (Coulomb)
• 1 volt = 1 joule per coulomb
• Electric circuit

  A closed path that electrons can travel through
• Electron

  Carries a certain amount of electrical energy and potential
• Battery

  Supplies the "push" that makes electrons move through the circuit
• Electromotive force (EMF)


  The maximum amount of energy that can be imparted by the source
• EMF

  Terminal potential difference (tpd) < EMF
• All batteries have internal resistance
• Current

  The flow of electric charge
• Charge

  The amount of charge
• Conventional current


  The direction of current flow from positive to negative
• Real (Electron) current


  The direction of electron flow from negative to positive
• Resistance

  The opposition to the flow of current
• Voltage (V)


  The potential difference across a component
• Conductors

  • All conductors have a certain degree of resistance
  • Copper is a good conductor
• Factors affecting resistance

  • Thinner= High
  • Thicker= Low
  • Shorter= Low
  • Colder= low
  • Thicker= High
  • Longer=
  • Warmer= High •Colder= low
• Resistance (R)

  The ratio of potential difference to the current (V/I)
• The current through a conductor is directly proportional to the potential difference across it, if the conductor is at a constant temperature