GCSE Science/Circuits

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GCSE Science/Electricity

You've probably done quite a lot of work in basic electrical circuits in lower school, but we will revise them here so don't worry if you've forgotten them.

Before we start you need to know a whole host of circuit symbols.

Q1)See how many of the following you can name:

Circuit symbols 1.png                          Circuit symbols 2.png

You should already know about half of them. For the others see here. You need to learn all these symbols by heart, but don't worry about that just yet. It's much easier to learn the symbols if you know what the components actually do, and we will be looking at that later on.

What is a circuit?[edit]

Simple bulb and switch circuit.png

A circuit is a loop in which electricity can flow. Consider a simple circuit with a cell, a switch and a bulb. The current flows from the cell, via the closed switch to the bulb. The bulb lights because the electricity carries energy. But even after the bulb there current still needs to go around the rest of the loop back to the cell. If there is a break anywhere in the loop, the bulb will not light. This is a concept that is not all that difficult, yet most people do not understand it.

Ask a selection of adults you know and many will say:
"Electricity flows from the cell to the bulb, where it gets used up"

Q2) What is wrong with the above statement?

Q3) Look at the selection of circuits below. What is wrong with each of them?


Three wrong circuits.png

What we have been looking at so far has been largely revision. You should already be familiar with what a circuit is and how it works. Let's now go on to some more advanced work.


<< Electrolysis | Current, voltage resistance and Ohm's law