Many GCSE Physics courses, including AQA Trilogy, include a compulsory practical to investigate the current-voltage (I-V) characteristics of various electrical components. This experiment links back to the work done by Georg Ohm, whose results have previously been summarised as; "the current flowing through a conductor is directly proportional to the potential difference (voltage) across the … Continue reading Investigating I-V Characteristics
Ohm’s Law
Potential difference (voltage) and current are fundamental measurements for electric circuits. Multiply the potential difference across a device by the current flowing through it to get the power rating for that device.Multiply the power rating by the time for which the device is used to get the energy that the device has transferred. All of … Continue reading Ohm’s Law
Energy Transfers in Electric Circuits
The amount of energy transferred in an electric circuit can be calculated by multiplying the current, time and potential difference. This is expressed in the equation given below. Current is measured in amps (amperes), time is in seconds, and potential difference in volts. Remember that the symbol for current is the letter I - not … Continue reading Energy Transfers in Electric Circuits
Resistance theory
Often it is true in physics that if you can understand one thing then it will automatically help you to understand something else. A good example of this occurs in resistance, where the model of resistance in a wire links directly to the behaviour of circuits that have resistors arranged either in series or in … Continue reading Resistance theory
Transformers
The famous "electricity war" between Edison and Tesla wasn't just about electricity generation, it was also about electricity distribution. Edison's DC electricity couldn't be sent very far due to power losses but Tesla's AC could go much further and benefit people over a much wider area. Efficient electricity distribution relies on minimising power loses due … Continue reading Transformers
Correct wiring of a 3-pin plug
There once was a time when the ability to wire a 3-pin plug was an essential skill - but not any more. For reasons of safety, many devices are now fitted with molded plugs that cannot be opened or removed. Nevertheless, the exam board still expects you to be able to identify the essential features … Continue reading Correct wiring of a 3-pin plug
Electrical Circuits: mini-test
It is really important that you check your understanding as you work through a topic. With that in mind, I have created a short online test that you can use to check your recall and understanding of some of the basic knowledge required for the Electricity module. You can access the test, which is hosted … Continue reading Electrical Circuits: mini-test
Current and Voltage rules
There is a clear pattern to the measurements of current and potential difference (voltage) in electrical circuits - which, for us, means series and parallel circuits. These two patterns were identified by Gustav Kirchhoff and are therefore known as Kirchhoff's Laws. Kirchhoff's current law states that the sum of the currents flowing into a junction … Continue reading Current and Voltage rules
Series and Parallel Circuits
Electric circuits are all about energy transfers: they allow the energy in the original source to be transferred via electricity into some other form. In the classic torch-bulb circuit, for example, chemical energy (in the cells) is converted into electrical energy, which is then converted into light (and heat, for old-fashioned bulbs). The amount of … Continue reading Series and Parallel Circuits
Can you beat 49/50?
Doing a test may not be your idea of a cool holiday activity but CGP (the publisher of your revision guide) has just released a series of free online GCSE tests that I highly recommend. You can access the tests at https://www.cgpbooks.co.uk/resources/free-gcse-science-10-minute-tests. On the landing page, select Separate Science then choose Physics. You will have … Continue reading Can you beat 49/50?