# Apply Standard Circuit Symbols

In this worksheet, students will revise standard circuit symbols, the function of each component and learn how to apply them in a circuit.

Key stage:  KS 4

Difficulty level:

### QUESTION 1 of 10

In the world of science, we have to talk to each other and communicate ideas a lot - this leads to scientists developing their own complex language so that they can pass on exactly what they mean with a high degree of accuracy. When it comes to electricity however, nothing beats a good old fashioned picture to try and show what you mean! The problem is that when you are looking at a drawing of them, the parts of a circuit can all look quite similar, so scientists needed to develop their own set of symbols to tell each other what they meant. This code allowed them to recreate electrical machines that electrocuted elephants, brought people back to life and got things to spin in circles really fast (all real electricity experiments in the 1900's). Now you too can break the code with this once in a lifetime chance to enter the world of the super scientist! Using our patented code-break tech, you can discover the hidden depths of electrical machines and recreate them yourself (only to be used with adult supervision). We are going to look at the symbols, their functions and their names here and then test you on them. Let's do it!

 Component Name Function Symbol Battery Provides a flow of electrons to the circuit. Has a positive (+ve) and a negative (-ve) terminal. Charge flows from the +ve terminal to the negative terminal. A battery is a bunch of cells all placed together. Cell Provides a flow of electrons to the circuit. Has a positive (+ve) and a negative (-ve) terminal. Charge flows from the +ve terminal to the negative terminal. A cell is a single unit in a battery (e.g. a AA battery is really a cell, but 2 AA batteries are a battery - confused yet?) Switch Turns the circuits on by allowing the charge to flow around the circuit (we call this a complete circuit when a charge is allowed to flow through it). This is a really simple one, you can see the break in the circuit. Ammeter Measures the current in the circuit. Must be placed in series. Voltmeter Measures the potential difference across a component. Must be placed in parallel. Resistor Slows the current in a particular place. They will normally have their particular resistance written inside them or just above them Lamp This is the symbol for a lamp or bulb in a circuit. Fuse This will break the circuit if the current gets too high. Variable Resistor A resistor that can change its value of resistance. LDR Stands for Light Dependent Resistor (not to be confused with LED). This will change its resistance depending on the amount of light. Normally, the more light the lower the resistance. Thermistor This will change its resistance depending on the temperature. Diode This is a device that will only allow current through in one direction. You see how it looks like an arrow - that is the direction that the current can flow in.  ​ LED This stands for Light Emitting Diode - it's a diode that shines.

Come back to this list with every activity you do in electricity in order to get a handle on these symbols and some of these words - it might take you a while, but you'll get used to it in time. You will be expected to know all of these - maybe make a poster of them that you can use when you are doing your revision?

You also need to know if a circuit is working or not. This is fairly simple - if you can trace your finger through the circuit without any breaks, then it is working. If there is a break, then it is not working! (This will get more complex when we look at series and parallel circuits, but for the moment this is all you need to know).

Let's get on to those questions now.

Match these symbols to their names.

## Column B

Lamp
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Battery
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Cell
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Voltmeter
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Ammeter
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For each of the rows below, select the correct component to match the meaning.

 Variable Resistor LED Diode Battery LDR Resistor Slows down the current by a set amount Changes resistance depending on the light Only allows current through in one direction Can change its resistance Gives off light

Match these symbols to their names - this one is going to be harder!

## Column B

Diode
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Thermistor
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Resistor
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Variable resistor
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LDR
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How would you connect a voltmeter?

Parallel

Series

Dominant

How would you connect an ammeter in a circuit?

Parallel

Series

Dominant

Match the image to the description of the component.

## Column B

Provides a current to the circuit
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Emits light while only letting current through in ...
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Emits light
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Changes resistance based on temperature
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Breaks the circuit if the current is too high
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Sandra is building a circuit for lighting a stage. She knows that if the current goes above 6 A, then it could damage the wiring in the circuit.

Name the component that Sandra could use to limit the current to below 6 A.

Max is building a circuit to operate in a fridge. He wants to be able to build a circuit to control the temperature, and when the light comes on.

Select the TWO components that Max needs to use as sensors in his experiment.

LED

Diode

Thermistor

Fuse

LDR

Switch

Resistor

Describe the similarities and differences between an LED and a diode.

[3]

Describe the difference between a cell and a battery.

[1]

• Question 1

Match these symbols to their names.

## Column B

Lamp
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Battery
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Cell
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Voltmeter
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Ammeter
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EDDIE SAYS
Some of these you can guess - they are obvious! The one with the V in it you should be able to guess is the voltmeter and the one with the A in it, hopefully you got as the ammeter. The cell and the battery might have messed you up a bit. All you have to do is remember that a battery is a bunch of cells put together - just like a battery of gunfire is lots of gunfire, a battery is lots of cells. Did you get the lamp? It literally has nothing to do with what it looks like but it is used so much that you will get used to it.
• Question 2

For each of the rows below, select the correct component to match the meaning.

 Variable Resistor LED Diode Battery LDR Resistor Slows down the current by a set amount Changes resistance depending on the light Only allows current through in one direction Can change its resistance Gives off light
EDDIE SAYS
As well as knowing the symbols for the components, you also need to know what they do. The best way to get to know these components is by using them in circuits, and we highly encourage you to have a go at this, using a low voltage battery to prevent electric shocks.
• Question 3

Match these symbols to their names - this one is going to be harder!

## Column B

Diode
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Thermistor
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Resistor
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Variable resistor
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LDR
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EDDIE SAYS
These ones are less likely to come up unless you are sitting the higher tier paper - apart from the resistor, that one you should know! If you take a look at all of these, you might start to see some patterns emerging. The resistors all have a box in them - this is the universal symbol for a resistor. Whether it is a thermistor, LDR, or a variable resistor, they will all have the resistor box in them. All diodes will have an arrow: the diode and the LED will both have an arrow showing you which way the current is able to go. Hopefully, remembering these tips will help you to learn some of the more difficult symbols.
• Question 4

How would you connect a voltmeter?

Parallel
EDDIE SAYS
The way you remember this is by thinking about what the voltmeter does. It will measure the potential difference between two places in the circuit. For it to do this, it needs to be connected at two points so that it can measure the difference between them, so it needs to be in parallel. Still don't get it - take a look at our series and parallel activity.
• Question 5

How would you connect an ammeter in a circuit?

Series
EDDIE SAYS
If you didn't guess correctly, then you might have been able to work this out by thinking about what it is that the ammeter does. It measures the current (the number of electrons passing a point every second), so it needs to be in a part of the circuit that electrons will flow through. This means that it needs to be in series. Have a look at the activity on series and parallel circuits if you're still not sure.
• Question 6

Match the image to the description of the component.

## Column B

Provides a current to the circuit
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Emits light while only letting cu...
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Emits light
');" onmouseout="tooltip.hide();">
Changes resistance based on tempe...
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Breaks the circuit if the current...
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EDDIE SAYS
For this one, you need to know both the symbol and the function of the component. These should become second nature to you and you'll want to revisit these questions a few times in order to really remember all of these symbols and their meanings.
• Question 7

Sandra is building a circuit for lighting a stage. She knows that if the current goes above 6 A, then it could damage the wiring in the circuit.

Name the component that Sandra could use to limit the current to below 6 A.

fuse
EDDIE SAYS
There are actually a lot of different components that could be used to achieve this. But if you want to make sure that the current doesn't go above a set amount, you will need the fuse. A fuse will break the circuit if it exceeds a specified amount of current.
• Question 8

Max is building a circuit to operate in a fridge. He wants to be able to build a circuit to control the temperature, and when the light comes on.

Select the TWO components that Max needs to use as sensors in his experiment.

Thermistor
LDR
EDDIE SAYS
There are two important words here. One of them is a word in bold that will get you some marks! Select the two answers - even if they are both guesses, select them! The second is the word sensor. All of the pieces of equipment listed above could be used in this circuit, but only a few of them could tell the circuit the temperature or the light level - these are the sensors. So, you are looking for something with temperature and something with light in their names - that leaves you with the thermistor and the LDR. Well done if you worked this one out because they are quite tricky components to get your head around.
• Question 9

Describe the similarities and differences between an LED and a diode.

[3]

EDDIE SAYS
Did you remember which one is which? They are both diodes (they both have diode in the name - think about what LED stands for) but only one can give off light. To get the three marks, you needed to outline the things that are similar about them - they are both diodes and they let current flow in only one direction and the things that are different - only the LED can give off light.
• Question 10

Describe the difference between a cell and a battery.

[1]

EDDIE SAYS
It's just one of those fundamental things that you need to remember: a battery is a collection of cells! A battery is a collection of cells! Oh, and did we mention - a battery is a collection of cells? We did, oh well - once more for good luck - a battery is a collection of cells! Do you think you can remember this now?! Well done for completing this very important activity. These components and their symbols really are one of the key things you need to actually learn for the exam.

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