Motors and Loudspeakers

Motors use the motor effect: both sides of a coil experience a force in opposite directions, and it turns.

A split-ring commutator is needed to ensure that the current is reversed every half turn, in order to keep the coil spinning.

Current always flows from positive to negative.

To increase speed:

• Add more turns to coil

• Increase p.d./current

• Use stronger magnet

Loudspeakers also use the motor effect: a current is sent from a source e.g. phone - this causes the coil and speaker cone to vibrate, producing sound waves.