Electrical systems and control

Systems (input, process, output), series and parallel, safety and control. Read one part at a time and tap “I know this”. Then test yourself in the quiz.

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Systems

Any system can be described like this.

System	Input	Output
Torch	Switch on	Light
Electric kettle	Electricity	Heat that boils the water
Burglar alarm	A movement sensor	Sound (siren)
Solar panel system	Sunlight	Electricity

A system controlled by a computer is an automated system.

Tap when you could tell someone without looking.

Circuits and safety

Series: one path. Parallel: each lamp has its own path.

Component or word	What it does
Resistor	Limits the current
Diode	Lets current flow one way only
Ammeter	Measures the current
Motor	Changes electricity into motion
Battery	Stores energy and releases it as electricity
Watt	The unit of electrical power

Copper is a good conductor. Thicker wire (for a stove) carries a larger current.
A short circuit: the current finds a path with very little resistance and becomes dangerously large.

Meerkat tip

Does a device spark? Switch it off and tell an adult. Never open it yourself.

Tap when you could tell someone without looking.

Remember this and test yourself

Remember this: your summary

Every system has an input, process and output.
A switch opens or closes the circuit; current flows only in a complete loop.
Series: one lamp burns out, all go out. Parallel (houses): each lamp can fail alone.
A fuse’s thin wire melts; a circuit breaker breaks a current that is too strong; the earth wire prevents shocks.
A sensor lets a system react to its surroundings; a thermostat is a system with feedback.

Write these points in your book. Read them again the night before the test.

Memory trick

Series is like people holding hands in a line: one lets go, all stop. Parallel is everyone on their own path.

Flash cards · Tap to turn over

Important words

First say what the word means, then turn the card over.

Test yourself · Part 2

True or false?

Read the question and the answer. Is the answer right? Tap True or False.

Now the real quiz!

The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.

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For parents

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