Ch 22 Magnetism III Producing Electric Current p
- Slides: 7
Ch. 22 - Magnetism III. Producing Electric Current (p. 633 -639) w Electromagnetic Induction w Electric Generator w DC & AC w Transformer
A. Electromagnetic Induction Ø Electromagnetic Induction w producing a current by moving a wire through a magnetic field w some microphones work just like minispeakers in reverse w sound waves cause coil to move current Coil Dynamic Microphone
B. Electric Generator Ø Electric Generator w mechanical energy electrical energy w armature is rotated between magnet poles w magnetic field induces a current in the wire coil GENERATOR MOTOR
B. Electric Generator Ø Hydroelectric Dam w PE of lake water is converted to KE w mechanical KE turns the generator shaft which creates electrical energy
C. DC & AC Ø Direct Current (DC) w current flows in one direction w dry cells Ø Alternating Current (AC) w current reverses its direction at regular intervals w electrical outlets
D. Transformer Ø Transformer w increases or decreases AC voltage w primary coil AC produces a magnetic field that induces AC in the secondary coil w voltage ratio = ratio of turns in each coil
D. Transformer Ø Step-up Transformer w increases the voltage w more turns w power plants Ø Step-down Transformer w decreases the voltage w fewer turns w household appliances (hairdryers, etc. )
