Spm physic Transfomer Transformer is a device that is used to raise or lower down the potential difference of an alternating current.

1. The Transfomer

2. What is a transformer?
A transformer allows you to change the current and
voltage values within that power equation.
P = IV

3. Transformer Construction
A transformer is a laminated, soft iron core with two insulated
coils of wire wrapped around it. The windings of the core are
made of low resistance copper.
Q1. Why must is be made of a soft magnetic material?
Easy to magnetised and demagnetised
Q2. Why must the core be laminated?
To reduce eddy current
Q3. Why do the windings have to be of low resistance?
To prevent electrical energy is wasted in the form of heat
energy.

4. How a transformer works
An alternating voltage (VP) is applied across the
primary coil.
This causes a changing magnetic field to be formed
around the primary coil.
The magnetic domains inside the soft iron core line up
in response to the magnetic field from the coil.
The secondary coil experiences the changing
magnetic field produced by the primary and the core.
It responds to this changing magnetic field by
producing a voltage (VS) across its ends (an induced
EMF) by electromagnetic induction.

5. Why must the source voltage
be an alternating voltage?
Electromagnetic induction only happens when a
wire loop experiences a changing magnetic field .
The Equation
There is a mathematical link between the number of
turns and the voltages on each coil.
V secondary
----------------- =
V primary
N secondary
------------------N primary

6. Thank you
Made by : Elaine Song
Sources :
http://www.cyberphysics.co.uk/topics/magnetsm/electro/Tra
nsfromer/trnsfrmr.htm