Electromagnets

Right hand grip rule
1. Grab the wire with the right fist, thumb pointing up or down depending on current. (+ to -)
2. Curled finger direction shows direction of the magnetic field
3. Thumb shows direction of current
Flemings left hand rule
1. Forefinger points to Field (N to S)
2. thuMb points to Movement
3. seCond finger points to Current
Motor Effect
1. When a current flows in a magnetic field it will produce MOTION
2. A magnetic field is created when an electric current flows through a wire. Electromagnets have strong magnetic fields due to the coiling of wire around a soft iron core. . When a magnetic field from a wire is placed into another magnetic field, it causes the wire to move. This principle is utilised in electric motors and loudspeakers.
3. Electromagnets are used in many appliances including electric bells and relay switches
Strength of an elctromagnet increases when -
1. More coils
2. Larger current
3. Stronger magnets
Electromagnetic Induction
1. If we move a conductor in a magnetic field we will produce a current
2. 1. Wire is moved through magentic field
  1. 2. This causes an electromagnetic field to be induced into the wire
    1. 3. The EMF induces a current in the wire
      1. 4. The current proiduces a magnetic filed which causes a 'drag' force in the wire in the opposite direction to the original motion.
Transformer Calculations
Transformers
1. Step up
  1. More coiuls in secondary,
  2. Increase voltage, decreases current
2. Step down
  1. less coils in secondary
  2. Decreases voltage, increase current

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Electromagnets

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	Created by Jack Milligan almost 8 years ago