Electromagnetic Induction

• Electromagnetic induction = a wire is move through a magnetic field which will cause a current to flow in the circuit.
• • As wire is moved down through the magnetic field, the current flows one way and as it’s pulled back out it flows the other way.
• Wire is moved upwards through magnetic field causing a current to flow (measured by ammeter).

  
• Size of current induced can be increased by increasing:

  • speed of movement - coil turning faster (increases current and frequency of current).
  • length of wire within magnetic field - more turns.
  • strength of magnetic field - stronger magnets or coil with larger area.
• Direction of the force can be determined by Flemings right hand rule

  
• Simple AC generator

  
• SIMPLE AC GENERATOR

  • As the coil of wire rotates, the wire cuts the magnetic field lines and induces a voltage - the slip rings are always connected to the carbon brush so a current will flow.
• SIMPLE AC GENERATOR

  1. In diagram, initial motion of the wire AB is upwards, meaning current will flow from A to B (Fleming‘s Right Hand Rule).
• SIMPLE AC GENERATOR

  2. As coil rotates past it’s vertical postition, the wire AB will move downwards, meaning current will change direction B to C.
• SIMPLE AC GENERATOR

  3. As coil continues to rotate, the induced current will change direction again - it will induce an alternating current.
• Alternating current