Electromagnetism
- whenever there is wire with a current going through it
- there is a (small) magnetic field around it
Right hand rule
- thumb is the current
- fingers are the magnetic field
How to increase the size of the magnetic field around a wire
- increase the current
- coil the wire
- add an iron core
Solenoid
- coil of wire (current on)
- with an iron core
- same magnetic field lines as that of a bar magnet
Motor effect
- a current-carrying wire will produce a small magnetic field
- if you place this wire between permanent magnets,
- the magnetic fields will interact
- this will create a force causing the wire will spin
- we can add a split-ring commutator to allow the wire to keep spinning the same direction
Fleming's left hand rule
- this rule can be used to determine the direction the wire will spin in
- first finger - field (north to south)
- second finger - current
- thumb - movement (force)
How to increase the force from the motor effect
- increase the length of the wire
- increase the current
- use stronger magnets
- move the magnets closer