force, energy & communication lesson 10 & 11 transformers
TRANSCRIPT
Force, Energy & Communication
Lesson 10 & 11
TRANSFORMERS
Lesson Objectives
Appreciate the role of transformers Understand how to make and use a
transformer To be distinguish between a step-up and
step-down transformer. To understand and be able to use the
transformer equation
NO! Not one of these!
That’s better, one of these!
PHYSICS TEXT BOOK
Turn to page 94
PHYSICS TEXT BOOK
Turn to page 94
Come round the front bench!
Really – they are just too camp!
Transformers
The job of a transformer is to change the voltage in a circuit.
Transformers
A step down transformer REDUCES the voltage in a circuit.
The input voltage is higher than the output voltage.
e.g. transformers found in electrical sub-stations
Transformers
A step up transformer increases the voltage in a circuit.
The input voltage is lower than the output voltage.
e.g. transformers used to convert USA voltage to UK voltage
What a transformer is made of Consists of two coils of wire wrapped around
a soft iron core. The coil attached to the INPUT voltage is
called the PRIMARY coil The coil attached to the OUTPUT voltage is
called the SECONDARY coil.
This is a STEP-UP transformer (more coils in the secondary than primary coil)
Collect an experiment sheet and carry out your own investigation into transformers.
Calculating the output voltage The output voltage can be calculated using
this formula:
Calculating the output voltage The output voltage can be calculated using
this formula:
secondary (output) voltage = no. of turns on secondary coil
primary (input) voltage no. of turns on primary coil
Worked example
A transformer has 960 turns on the primary coil and 16 turns on the secondary coil. The primary coil is connected to 230V a.c.. What will be the output?
Worked example
A transformer has 960 turns on the primary coil and 16 turns on the secondary coil. The primary coil is connected to 230V a.c.. What will be the output?
secondary voltage = 16
230 V 960
Worked example
A transformer has 960 turns on the primary coil and 16 turns on the secondary coil. The primary coil is connected to 230V a.c.. What will be the output?
secondary voltage = 16
230 V 960
So the secondary voltage = 230 X (16/960)
=
Worked example
A transformer has 960 turns on the primary coil and 16 turns on the secondary coil. The primary coil is connected to 230V a.c.. What will be the output?
secondary voltage = 16
230 V 960
So the secondary voltage = 230 X (16/960)
= 3.9 V
Collect “The transformer – data analysis”
Carry out all the exercises on this sheet.
Collect “The transformer – data analysis”
Carry out all the exercises on this sheet.
HW Complete the questions on the sheet
“TRANSFORMERS” – hand in on Thursday.
Lesson Objectives
Appreciate the role of transformers Understand how to make and use a
transformer To be distinguish between a step-up and
step-down transformer. To understand and be able to use the
transformer equation