Download Notes Sec 4.4

Science 10
Chapter 4
4.4 ELETRIC GENERATORS
If a current can produce a magnetic field, can a magnetic field produce a
current?
YES – that is what electric generators do!
ELECTRIC GENERATORS: any device that can change electrical energy
into mechanical energy
Micheal Faraday made to the first generator in 1831
Diagram, Pg 82
- Generators produce electricity by moving a conductor through a magnetic
field or by changing the magnetic field surrounding the conductor. Each
procedure exerts a force on the electrons in the conductor and results in the
electrons moving through it.
- A coil and magnet moving back and forth act as the generator of electricity
because the movement of the magnet changes the magnetic field around the
coil.
GALVANOMETER: is a device that can measure currents produced from
an electric generator
Science 10
Chapter 4
ALTERNATING CURRENT (AC current)
- Current that can flow in both directions
- It is produced in a generator and changes direction 120 times per
second
An oscilloscope is used to measure the change in direction
DIRECT CURRENT (DC current)
- current that can only flow in one direction
- it is produced in a battery ( - to +) and only flows in one direction
- explains why an ammeter needle does not change
- TV’s and appliances use DC
ELECTRIC MOTORS vs. ELECTRIC GENERATORS
- electric motors change electrical energy into mechanical energy, therefore;
they are opposite to electric generators