Idea 3of 4Builds onFaster change, bigger swingA current in a field feels a push
Spin it
Turn a coil between two magnets. What comes out?
Today you'll discover
- what a coil turning in a field produces
- why the current keeps changing direction
- the motor run backward
Think firstA coil is turned steadily between two magnets
A coil is turned steadily between two magnets. What does the meter show?
Decide first, then press Next. Watch the needle and the graph as the coil turns.
A north pole at the left and a south pole at the right with a rectangular loop between them, a meter dial above and a small graph along the bottom. After a prediction, the loop turns a quarter at a time: the needle swings widest, passes zero edge on, swings the other way, and the graph traces one cycle. The last step turns it twice as fast and asks what changes.
See the whole ideathe big idea and the key word, in one place
The big idea
A generator: a turning coil makes a current that reverses.
Where it goes nextThe grid's power stations are this coil, turned by steam, water or wind. The reversing current they make is AC, and that is the next topic.
Key word
- generator
- a coil turned in a magnetic field, so that the changing field through it induces a voltage; mechanical energy in, electrical energy out
About this modelThe graph under the coil is the voltage over one turn, not a picture of the coil's path.
The graph under the coil is the voltage over one turn, not a picture of the coil's path.
Ready to use it?
- Describe what the current from a described generator does over one turn, and what turning it faster changes.