Transcript Transformers

Transformers
► Electric
Generators- the main function of an
electric generator is to convert mechanical
energy to electrical energy.
► Electric motors- main function of an electric
motor is to convert electrical energy into
mechanical energy.
Transformer
►A
device that increases or decreases the
emf of alternating current.
► Reminder: emf is the energy per unit charge
supplied by a source of electric current.
AC Transformer
consists of two coils of
wire wound around a
core of soft iron.
► The coil on the right
has N1 turns and is
connected to an input
ac potential difference
source. This is called
the primary winding.
►
► The
coil on the left is
connected to a resistor
R and consists of N2
turns, is the
secondary.
► The difference
between the two is the
amount of turns N
Transformer equation
► ΔV2=N2 V1
N1
Step-up
► When
N2 is greater
than N1 the secondary
emf is greater than the
primary making it a
step up transformers.
Step Down
► When
N1 is greater
than N2 the secondary
emf is less than that of
the primary making it
a step-down
transformers.
Examples