What is current?
In GCSE physics, current is the flow of charge per unit time. The charge carriers in an electrical circuit are the free electrons that flow around the circuit when a potential difference or voltage is introduced. Each electron has a charge; the amount of charge passing a fixed point in a circuit, such as an ammeter, is the current.
Current is measured in amperes, or amps (A) by an ammeter. Ammeters must be placed in series to allow the current to flow through.
Current is the same everywhere in a series circuit because there is only one path for the electrons to flow through.
In a parallel circuit, the current is different at different places in the circuit. This is because the electrons have more than one path they can take. The sum of the current in the individual branches is always equal to the total current of the circuit.
Conventional current flows the opposite way around a circuit to the negative electrons. Electricity was already widely used when the electron was discovered; therefore, the idea of conventional current is still in use. Conventional current flows in the direction that a positive charge would flow around a circuit, from the positive terminal to the negative terminal.
Electron flow shows the direction that electrons actually do flow around a circuit: from the negative terminal to the positive terminal.
All specifications and exam questions use ‘current’ to mean conventional current.
Current revision resources to ace your exams
You can strengthen your understanding of current by using our revision notes tailored specifically for the AQA, Edexcel, WJEC and OCR exam boards.
You can practice electricity questions and calculations with helpful guidance and examiner tips using our exam board specific GCSE Physics exam questions.
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Written by Leander Oates
Physics19 articlesLeander graduated with First-class honours in Science and Education from Sheffield Hallam University. She won the prestigious Lord Robert Winston Solomon Lipson Prize in recognition of her dedication to science and teaching excellence. After teaching and tutoring both science and maths students, Leander now brings this passion for helping young people reach their potential to her work at SME.
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