1437172
Descripción
Mapa Mental por andrewmoakes100, actualizado hace más de 1 año
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Creado por andrewmoakes100
hace alrededor de 10 años
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ELECTRO MAGNETIC INDUCTION
ANDREW MOAKES
- VOLTAGE INDUCTION
- Voltage is induced across a wire
when it cuts through a magnetic
field
- the wire cuts through the field
lines up and down
- Voltage is induced across a wire
when it cuts through a magnetic
field
- electromagnetic induction
- The EMF (electromotive force) or voltage induced across a conductor
is directly proportional to the rate at which the field lines are cut V∝
NUMBER OF FIELD LINES CUT PER SECOND
- Flemings right hand rule
- this is used for a wire moving through a magnetic field.
thuMb=motion First finger=field seCond finger=current
- Rotating the coil twice as fast =
2xAmplitude and 2xNumber of
oscillations
- The EMF (electromotive force) or voltage induced across a conductor
is directly proportional to the rate at which the field lines are cut V∝
NUMBER OF FIELD LINES CUT PER SECOND
- AC generator
- As the coil spins the wires on the side of the coil cut the magnetic field
lines. The induced voltage drives a current which flows through slip rings
which press against carbon brushes. As the generator spins round, the
current in the circuit change direction. Hence the name alternating current
generator.
- To increase the voltage 1)More turns of wire
on coil. 2) stronger magnet 3) Larger area of coil
4) Faster speed of movement
- As the coil spins the wires on the side of the coil cut the magnetic field
lines. The induced voltage drives a current which flows through slip rings
which press against carbon brushes. As the generator spins round, the
current in the circuit change direction. Hence the name alternating current
generator.
- TRANSFORMERS
- A transformer is used to change the voltage of an
AC SUPPLY
- transformer equation: Vp/Vs = Np/Ns V
is voltage N is number of turns P is
primary and S is secondary
- Step up transformers increase
voltage Ns is bigger than Np
- Step down transformers decrease voltage Np is bigger than Ns
- 1) An alternating current flows through the transformer. 2)This creates
a changing magnetic field in the iron core 3)the changing magnetic field
is cut by the secondary coil. 4)This induces a voltage across the
secondary coil 5)This is an alternating voltage to the changing direction
of the magnetic field 6) The size of the induced voltagedepends onthe
ratio of number of turns of each coil
- Transformer efficiency Use thicker wire or use a
laminated core making it more difficultfor current to flow
in the coil.
- A transformer is used to change the voltage of an
AC SUPPLY
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