|
GCSE level physics:
National Grid electricity supply:
Part 6.5
More on the uses of transformers -
many everyday 'appliances' and devices in the home use a transformer
[Author
©
Dr WP Brown PhD:
Doc Brown's physics exam revision notes suitable for students studying UK
IGCSE & GCSE level physics courses, ~ US grades 9-10 physics, page updated
Feb 16th 2026 *]
[KEY
POINTS and learning objectives for this page, after initial notes]
*
[email doc b]
*
[privacy]
INDEX for physics notes on
National Grid power supply, use of transformers-calculations and
environmental issues
6.5 More on the uses of transformers
Battery charging
Transformers are used to control the voltage that enters the battery
during the charging process in order to prevent any damages that can
occur to the internal battery components.
So, transformers are used in many
devices in the home to convert the mains electricity p.d. of ~230 V
down to a smaller safer voltage e.g. charging up your computer
battery or mobile phone battery.
The laptop adapter for my website
consists of the mains supply and transformer to create a much smaller
safer voltage.
Technically, when you
plug in the adapter, what is basically does what a
transformer does, but its NOT a simple transformer, technically
it is what is known as a 'switched-mode power supply.
Inside the adaptor 100-240
V AC (50/60 Hz)1.5 A mains supply and converts it to 19 V 3.16 A DC output.
Steel manufacturing
Steel manufacturing plants use
high/low voltage transformers to provide a range of voltages for the
manufacturing process - regulation of the current flowing.
High
currents are required for the melting and welding of steel, and
lower current are required during the cooling process.
Electrochemicals
In chemical engineering and
manufacturing processes, electrolysis is normally fuelled by the
functioning of transformers to control both the p.d. and current
flowing in e.g. electrolysis processes.
Metals used for
electroplating include copper, zinc, and aluminum and during the
process, transformers provide a regulated electrical current to
effect the chemical plating reaction.
National Grid system
The use of transformers in the
National Grid system has already been described on this
page.
Transformers enable the National
Grid system to efficiently deliver electricity to all parts of a
country.
The National Grid makes
extensive use of step-up and step-down transformers.
Transformers come in all sizes in
terms of physical size and power output e.g. from laptop computer
charger to large step-up transformers at power stations of the National
Grid electricity supply.
The small transformer converts the
higher voltage supply to a lower one appropriate for domestic supply.
INDEX of notes on
National Grid power supply & use of transformers
Key points about
the
electrical power industry
Information
sources for Doc Brown's key points: IGCSE-GCSE physics are based on
textbooks & syllabus-specifications for students taking the UK AQA, Edexcel,
OCR 21st Century Science, OCR Gateway science suite, WJEC, CCEA and CIE GCSE
physics 9-1 level science examinations
Here's a syllabus-aligned summary
of the use of transformers in the home, tailored for
students preparing for GCSE/IGCSE Physics across AQA,
Edexcel, OCR, WJEC, CCEA, and CIE.
Use of Transformers
in the Home
1.
Why Transformers Are Needed
- The mains electricity supply
in the UK is 230 V a.c., which is suitable for most
household appliances.
- However, some devices require
lower voltages (e.g. 5 V, 9 V, 12 V) to operate safely and
efficiently.
- Transformers
are used to step down the voltage from the mains to the
required level.
2.
Examples of Transformers in the Home
| Appliance/Device |
Voltage Supplied |
Transformer Use |
| Phone charger |
5 V |
Steps down 230 V to USB-compatible
voltage |
| Laptop charger |
19 V |
Converts mains voltage to safe DC
supply |
| Doorbell systems |
12 V |
Uses a transformer in the fuse box |
| Electric toothbrush base |
~12 V |
Inductive charging via low-voltage
transformer |
| TVs and game consoles |
Varies |
Internal transformer circuits regulate
voltage |
These are often isolating
transformers or adapters that include
rectifiers to convert a.c. to d.c. as well.
3.
How They Work
- Transformers use electromagnetic
induction and only work with alternating current (a.c.).
- A step-down transformer
has fewer turns on the secondary coil than the primary
coil.
- This reduces the potential
difference while increasing the current,
maintaining power (assuming 100% efficiency).
Exam-Board Friendly Summary
of content on transformers
| Concept |
Explanation |
| Transformer |
Device that changes the voltage of
a.c. using electromagnetic induction. |
| Step-down transformer |
Reduces voltage for safe use in
low-voltage devices. |
| Domestic use |
Found in chargers, adapters, and some
lighting systems. |
| Safety |
Prevents damage to sensitive
electronics and reduces risk of electric shock. |
Student Tips for Exam Success
What to Memorise:
- Transformers only work with
a.c.
- Step-down =
fewer turns on secondary coil
- Common household uses (chargers,
doorbells, etc.)
Common Exam Questions involving the use of
transformers:
- Describe how a transformer is used in a
phone charger.
- Explain why transformers are needed in
domestic appliances.
- Identify whether a transformer is step-up
or step-down based on coil turns.
Top Tips:
- Use real-life examples to
support your answers.
- Practice using the transformer
equation:
- Be ready to label diagrams
of transformer setups.
Keywords, phrases and learning objectives for National Grid electricity supply
Be able to describe and explain the uses of transformers
e.g. in battery chargers for mobile
phones, power supply to a computer, as wells as the many electrical
machines used in industry.
WHAT NEXT?
TOP of page
INDEX for physics notes on
National Grid power supply, use of transformers-calculations &
environmental issues
ALL my electricity and magnetism
notes
email doc
brown - comments - query?
INDEX of all my PHYSICS NOTES
Basic Science Quizzes for
UK KS3 science students aged ~12-14, ~US grades 6-8
Biology * Chemistry
* Physics for UK
GCSE level students aged ~14-16, ~US grades 9-10
Advanced Level Chemistry
for pre-university age ~16-18 ~US grades 11-12, K12 Honors
Find your GCSE/IGCSE
science course for more help links to all science revision notes
Based on the syllabus-specifications
for students taking the IGCSE/GCSE level physics examinations summary
revision notes and key points on use of transformers in the home e.g.
battery chargers for students taking the AQA
igcse/gcse physics notes on use of transformers in the home e.g. battery
chargers, Edexcel gcse
physics notes on use of transformers in the home e.g. battery
chargers, OCR 21st century GCSE
physics notes on use of transformers in the home e.g. battery
chargers, OCR gateway
GCSE physics notes on use of transformers in the home e.g. battery
chargers, WJEC gcse physics notes on use of transformers in the home
e.g. battery chargers, CCEA
gcse physics notes on use of transformers in the home e.g. battery
chargers for students taking CIE Cambridge igcse
physics, or any other GCSE or IGCSE level physics exams notes on
use of transformers in the home e.g. battery chargers, useful for US grade 9-10 physics courses,
Explaining the importance of use of
transformers in in devices/appliances for safe voltage
in GCSE level physics, What you need to know about use of transformers
in in devices/appliances for safe voltage for
GCSE level
physics,
Explaining what is the use of use of transformers in in
devices/appliances for safe voltage knowledge in GCSE level physics, Examples of
use of transformers in in devices/appliances for safe voltage explained
when studying GCSE level physics, What is
the significance of use of transformers in in devices/appliances for
safe voltage in GCSE level physics, Describing and
explaining the theory of use of transformers in in devices/appliances
for safe voltage when studying GCSE level physics, revision
notes for use of transformers in in devices/appliances for safe voltage in exams, online exam help for
use of transformers in in devices/appliances for safe voltage, revision notes for
use of transformers in in devices/appliances for safe voltage, what do I need to learn about
use of transformers in in devices/appliances for safe voltage for by GCSE physics exam?
revision summary for use of transformers in in devices/appliances for
safe voltage, help in teaching use of transformers in in
devices/appliances for safe voltage, learning notes for use of
transformers in in devices/appliances for safe voltage,
help to understand the use of transformers in in devices/appliances for
safe voltage topic in preparation GCSE physics exam
question, how to
prepare for questions involving use of transformers in in
devices/appliances for safe voltage in a GCSE physics examination?
SITEMAP
Website content © Dr
Phil Brown 2000+. All copyrights reserved on Doc Brown's physics revision notes, images,
quizzes, worksheets etc. Copying of website material is NOT
permitted. Exam revision summaries and references to GCSE science course specifications
are unofficial.
INDEX of notes on
National Grid power supply & use of transformers
|
