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0
G
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06/12/2025
Physics
GCSE AQA electricity
168
•
6 Dec 2025
•
GCSE AQA Electricity Revision Notes
G
G
@gurneet
1 / 5
Electrical Circuits and Current
Ever wondered what actually happens when you flip a light switch? Electric current is simply the flow of electrical charge around a closed circuit - think of it like water flowing through pipes. The current stays the same throughout a single loop, just like water flow in a continuous pipe.
You can calculate how much charge flows using this handy formula: charge flow = current × time. Current is measured in amperes (amps), time in seconds, and charge in coulombs.
The relationship between current, resistance, and potential difference follows a simple rule: potential difference = current × resistance. This means if you increase the resistance in a circuit (like adding more obstacles), less current will flow for the same voltage.
Quick Tip: Think of electrical resistance like traffic jams - the more resistance, the slower the flow!
How Different Components Behave
Not all electrical components behave the same way! Ohmic conductors (like basic resistors) keep the same resistance no matter how much current flows through them - they're predictable and reliable.
But other components are more interesting. Filament lamps get hotter as more current flows, which increases their resistance. Diodes only let current flow in one direction, acting like electrical one-way streets with very high resistance in the reverse direction.
Thermistors are temperature-sensitive - their resistance decreases as temperature rises. That's why they're perfect for thermostats in heating systems. Light Dependent Resistors (LDRs) do something similar with light - less resistance when it's bright, more resistance in darkness.
Understanding series and parallel circuits is crucial. In series, current flows through each component one after another, and resistances add up. In parallel, current splits into different paths, and total resistance actually decreases.
Remember: More paths in parallel circuits means less overall resistance - like opening extra lanes on a motorway!
Mains Electricity and Safety
Your home's mains electricity runs on alternating current (AC) at 230V and 50Hz - this means the current constantly changes direction 50 times per second. This differs from direct current (DC) from batteries, which flows in only one direction.
Every electrical appliance uses a three-core cable with colour-coded wires. The brown live wire carries 230V from the supply, the blue neutral wire completes the circuit at 0V, and the green and yellow earth wire provides crucial safety protection.
Here's the dangerous bit: even when a switch is off, the live wire still carries 230V. Touch it, and your body becomes a path to earth - that's how electric shocks happen. The earth wire protects you by providing a safer route for fault currents.
Safety systems work because when the live wire accidentally touches earth, the huge voltage difference (230V to 0V) causes a massive current surge that trips protective devices.
Safety First: Never touch exposed wires - the live wire is always dangerous, even when appliances are switched off!
Power and Energy Transfer
Power tells you how quickly an electrical device uses energy, measured in watts. You can calculate it using: power = potential difference × current, or power = current² × resistance. Higher power means more energy consumption.
Every electrical appliance transfers energy from one form to another. Your kettle converts electrical energy to heat, your phone converts it to light and sound. The energy transferred depends on both power rating and time: energy transferred = power × time.
You can also calculate energy transfer using: energy transferred = charge flow × potential difference. This shows that moving more charge through a higher voltage transfers more energy.
Understanding power ratings helps you choose efficient appliances and predict electricity bills. A 2000W kettle uses energy twice as fast as a 1000W kettle.
Money Saver: Check power ratings when buying appliances - lower wattage often means lower running costs!
The National Grid and Static Electricity
The National Grid is like a massive electrical motorway system connecting power stations to your home. Step-up transformers increase voltage for long-distance transmission (reducing energy losses), whilst step-down transformers reduce it back to safe levels for domestic use.
This high-voltage transmission system makes the grid incredibly efficient - much like sending data through fibre optic cables rather than old copper wires.
Static electricity forms when you rub insulating materials together. Electrons transfer from one material to another, creating positive and negative charges. You've experienced this when your hair sticks to a balloon or you get shocked touching a car door.
Electric fields surround any charged object, getting stronger as you get closer. When two charged objects meet, they either attract (opposite charges) or repel (same charges) - these are non-contact forces that work through the electric field.
Fun Fact: Lightning is just massive static electricity discharge between clouds and earth!
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This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
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Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
GCSE AQA Electricity Revision Notes
G
G
@gurneet
Electricity powers our everyday lives, from your mobile phone to your home's lighting system. Understanding how electric current flows, how circuits work, and why safety measures exist will help you make sense of the electrical world around you.
Electrical Circuits and Current
Ever wondered what actually happens when you flip a light switch? Electric current is simply the flow of electrical charge around a closed circuit - think of it like water flowing through pipes. The current stays the same throughout a single loop, just like water flow in a continuous pipe.
You can calculate how much charge flows using this handy formula: charge flow = current × time. Current is measured in amperes (amps), time in seconds, and charge in coulombs.
The relationship between current, resistance, and potential difference follows a simple rule: potential difference = current × resistance. This means if you increase the resistance in a circuit (like adding more obstacles), less current will flow for the same voltage.
Quick Tip: Think of electrical resistance like traffic jams - the more resistance, the slower the flow!
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How Different Components Behave
Not all electrical components behave the same way! Ohmic conductors (like basic resistors) keep the same resistance no matter how much current flows through them - they're predictable and reliable.
But other components are more interesting. Filament lamps get hotter as more current flows, which increases their resistance. Diodes only let current flow in one direction, acting like electrical one-way streets with very high resistance in the reverse direction.
Thermistors are temperature-sensitive - their resistance decreases as temperature rises. That's why they're perfect for thermostats in heating systems. Light Dependent Resistors (LDRs) do something similar with light - less resistance when it's bright, more resistance in darkness.
Understanding series and parallel circuits is crucial. In series, current flows through each component one after another, and resistances add up. In parallel, current splits into different paths, and total resistance actually decreases.
Remember: More paths in parallel circuits means less overall resistance - like opening extra lanes on a motorway!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Mains Electricity and Safety
Your home's mains electricity runs on alternating current (AC) at 230V and 50Hz - this means the current constantly changes direction 50 times per second. This differs from direct current (DC) from batteries, which flows in only one direction.
Every electrical appliance uses a three-core cable with colour-coded wires. The brown live wire carries 230V from the supply, the blue neutral wire completes the circuit at 0V, and the green and yellow earth wire provides crucial safety protection.
Here's the dangerous bit: even when a switch is off, the live wire still carries 230V. Touch it, and your body becomes a path to earth - that's how electric shocks happen. The earth wire protects you by providing a safer route for fault currents.
Safety systems work because when the live wire accidentally touches earth, the huge voltage difference (230V to 0V) causes a massive current surge that trips protective devices.
Safety First: Never touch exposed wires - the live wire is always dangerous, even when appliances are switched off!
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Power and Energy Transfer
Power tells you how quickly an electrical device uses energy, measured in watts. You can calculate it using: power = potential difference × current, or power = current² × resistance. Higher power means more energy consumption.
Every electrical appliance transfers energy from one form to another. Your kettle converts electrical energy to heat, your phone converts it to light and sound. The energy transferred depends on both power rating and time: energy transferred = power × time.
You can also calculate energy transfer using: energy transferred = charge flow × potential difference. This shows that moving more charge through a higher voltage transfers more energy.
Understanding power ratings helps you choose efficient appliances and predict electricity bills. A 2000W kettle uses energy twice as fast as a 1000W kettle.
Money Saver: Check power ratings when buying appliances - lower wattage often means lower running costs!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The National Grid and Static Electricity
The National Grid is like a massive electrical motorway system connecting power stations to your home. Step-up transformers increase voltage for long-distance transmission (reducing energy losses), whilst step-down transformers reduce it back to safe levels for domestic use.
This high-voltage transmission system makes the grid incredibly efficient - much like sending data through fibre optic cables rather than old copper wires.
Static electricity forms when you rub insulating materials together. Electrons transfer from one material to another, creating positive and negative charges. You've experienced this when your hair sticks to a balloon or you get shocked touching a car door.
Electric fields surround any charged object, getting stronger as you get closer. When two charged objects meet, they either attract (opposite charges) or repel (same charges) - these are non-contact forces that work through the electric field.
Fun Fact: Lightning is just massive static electricity discharge between clouds and earth!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Most popular content: Electric Potential
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English - inspector calls quotes and analysis
Quotes from every main character
English Literature10
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user