Applications

• In a direct current (d.c) the electrons flow in a singular direction.

• In an alternating current (a.c) the direction of flow is reversed in regular time periods.

• A.C Generator:

  • The coil is made of insulated copper wire and is rotated by turning the shaft; the slip rings are fixed to the coil and rotate with it.

  • The brushes are 2 contacts which rub against the slip rings and keep the coil connected to the outside part of the circuit, usually made of carbon.

  • When the coil is rotated, it cuts magnetic field lines, so an EMF is generated, which makes a current flow.

  • Each side of the coil travels upwards then downwards then upwards etc. so the current flows backwards then forwards then backwards etc. so it is an alternating current.

• The current is maximum when the coil is horizontal since field lines are being cut at the fastest rate and 0 when the coil is vertical, since it is cutting NO field lines.

• The EMF can be increased by:

  • increasing the number of turns on the coil

  • increasing the area of the coil

  • using a stronger magnet

  • rotating the coil faster