Download Transformer

Transformer
~can either “step up” or “step down” the
voltage provided to it.
 i.e. with the appropriate transformers you
could make a 12 V current 24 V or 6 v.
 Or 120 V can be 6 V
 It is created by wrapping two different
wires around the same conductor

Transformer
input
Power source
output
Primary
Secondary
How a transformer works
The change is caused by the number of
loops (turns) on the primary and
secondary.
 Assume both have 1 turn (loop), and the
primary is a 12 V source
 then the primary would induce a magnetic
field in the conductor, which will induce an
electric current in the secondary with 12 V

Now transforming
If the primary 1 V has one turn and the
secondary has two turns, then each loop
will get a 1 V, so it will have a total of 2 V.
 If the primary 2 V has two turns and the
secondary has one turn, the secondary will
have 1 V.
 One of the major reasons AC is used as
the primary power source is the ease in
stepping up or stepping down the voltage
as needed

Step up transformer
input
Power source
output
Primary
Secondary
Equation
Primary voltage = Secondary voltage
# of primary turns # of secondary turns
 If the power in the lines is 120 V with 20
turns going into a transformer with 10
turns what will the voltage be?
 V1 / T1 = V2 / T2
 120/ 20 = V2 / 10
 =60 V

Power line transmission
To transfer electricity across long
distances you have to use extremely high
voltage (like 120,000 V) and low current
 Otherwise you lose a lot of energy due to
heating of the wire
 Transformers easily step down the voltage
to 120 V used in our homes, or up to a
good amount to transfer it

Electromagnetic Radiation
electromagnetic induction occurs without a
wire for the current to travel through.
 Moving any charged object (like a balloon
rubbed on your head) will create…
 A moving magnetic field which in turn will
create…
 A moving electric field which causes…
 This continuously repeats
 This wave moves through space.

EM wave
Electromagnetic waves
Since the waves travel due to a constant
electromagnetic induction they always
travel at the same speed.
 This speed is exceptionally fast, as a
matter of fact it is the fastest anything can
ever go
 This speed is….
 3.0 x 108 m/s in a vacuum.

homework
Pg 758
 11-16; 19-22
