pmt definitions

• Alternator


  A device that makes use of the generator effect to generate alternating current
• Attraction

  Opposite poles will experience a force of attraction, meaning they will experience a force towards each other. The force between a magnet and magnetic material is always one of attraction
• Current-Carrying Wires


  When current flows through a wire, a magnetic field is generated around it. The strength of the field is dependent on the magnitude of the current and the distance from the wire
• Dynamo

  A device that makes use of the generator effect to generate direct current
• Electric Motor


  A current-carrying coil of wire in a magnetic field. The two sides of the coil that are perpendicular to the magnetic field experience forces in opposite directions, causing rotation
• Electromagnet


  A solenoid with an iron core
• Fleming's Left-Hand Rule


  A rule used to determine the orientation of the force (thumb), current (second finger) and magnetic field (first finger) when a current-carrying wire is placed in a magnetic field (motor effect)
• Generator Effect


  When there is relative motion between an electrical conductor and a magnetic field, a potential difference will be induced across the ends of the conductor. A current will flow if this conductor is part of a complete circuit
• Induced Magnet


  A material that becomes a magnet when it is placed in an existing magnetic field, but loses its magnetism quickly once it is removed. Induced magnetism always produces attractive forces
• Magnetic Compass


  A device containing a small bar magnet that points in the direction of the Earth's magnetic field
• Magnetic Field Lines

  Lines representing the strength and direction of a magnetic field. The field line direction at any point is in the direction that a force would act on another north pole if placed at that point
• Magnetic Field

  The region around a magnet in which another magnet or magnetic material will experience a force
• Magnetic Materials

  • Iron
  • Steel
  • Cobalt
  • Nickel
• Magnetic Poles

  The regions of a magnet where the magnetic forces are at their strongest
• Microphone

  A device that uses the generator effect to convert the pressure variations of sound waves into variations in the electrical current of a circuit
• Motor Effect


  When a current-carrying wire is placed in a magnetic field, a force will be experienced between the wire and the magnet responsible for the field
• Permanent Magnet


  A magnet that produces its own magnetic field
• Repulsion

  Like-poles will experience a force of repulsion, meaning they will experience forces in opposite directions
• Solenoid

  A wire wrapped into the shape of a coil, that has a strong and uniform magnetic field inside of it. The solenoid's magnetic field strength can be increased by adding an iron core
• Step-Down Transformer

  A transformer that has a smaller potential difference in the secondary coil than in the primary core
• Step-Up Transformer

  A transformer that has a larger potential difference in the secondary coil than in the primary core
• Tesla

  The unit of magnetic flux density
• Transformer

  An iron core with a primary and secondary coil of wire wound around opposite ends