A
transformer
works
on
the
principles
of
electromagnetic
induction
.
It
works
using
an
____________________
current
.
The
differences
between
a
direct
current
and
an
alternating
current
are
:
1
)
Alternating
current
____________________
____________________
from
positive
to
negative
continually
2
)
Alternating
current
has
varying
____________________
A
transformer
consisted
of
two
coils
of
wire
wrapped
around
a
core
.
This
core
is
usually
made
from
____________________
because
it
is
a
____________________
or
a
soft
____________________
material
.
A
lamp
in
the
secondary
coil
of
a
transformer
would
not
lit
if
there
is
____________________
current
in
the
primary
coil
because
there
is
no
change
in
or
no
cutting
of
____________________
____________________
,
therefore
there
will
be
no
electromagnetic
____________________
.
