Which of these is analogue data?

the temperature of a room. It changes smoothly and can take any value.

What kind of data can a computer process?

digital only. Everything must be turned into binary first.

converts analogue data to digital. Analogue in, digital out.

Why is a DAC needed in a control system?

so the computer's digital output can operate devices such as motors. Many devices need an analogue signal.

In what form is digital data stored?

as binary digits, 1s and 0s. Two values, on and off.

Analogue and digital data · Cambridge IGCSE Information & Communication Technology

In plain words

The world outside a computer changes smoothly: temperature drifts up and down, sound rises and falls. Inside a computer, everything is numbers made of 1s and 0s. Something has to translate between the two.

5 things to know

Analogue data varies continuously and can take any value in a range, such as temperature, sound and light.
Digital data is made of separate values, stored as binary digits: 1s and 0s.
A computer can only process digital data.
An analogue-to-digital converter (ADC) changes analogue data into digital, so that readings from a sensor can be processed by a computer.
A digital-to-analogue converter (DAC) changes digital data into analogue, so that a computer can control devices such as motors and speakers.

Worked example

A computer controls the heating in a greenhouse using a temperature sensor and a heater. Where are the two kinds of converter needed?

The sensor produces an analogue signal. An ADC converts it to digital so the computer can process it.
The computer's output is digital. A DAC converts it to an analogue signal that can operate the heater.

Tips and tricks

Sensors send analogue data, so the answer to "why is an ADC needed?" is always: the computer only understands digital data.

5 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Analogue and digital data: 5 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

Which of these is analogue data?
- a number stored in a spreadsheet
- the temperature of a room (the answer)
- a binary code
- a file on a disk
It changes smoothly and can take any value.
What kind of data can a computer process?
- analogue only
- digital only (the answer)
- both without conversion
- neither
Everything must be turned into binary first.
What does an ADC do?
- converts digital data to analogue
- converts analogue data to digital (the answer)
- stores data
- displays data
Analogue in, digital out.
Why is a DAC needed in a control system?
- so the computer can read sensors
- so the computer's digital output can operate devices such as motors (the answer)
- to store the readings
- to print the results
Many devices need an analogue signal.
In what form is digital data stored?
- as waves
- as binary digits, 1s and 0s (the answer)
- as letters only
- as pictures only
Two values, on and off.

5 questions

Tap an answer and you’ll see straight away whether it’s right, and why.

Worksheet

2 questions, 4 marks. Write your answers on paper, then check them.

Analogue and digital data

Cambridge IGCSE Information & Communication Technology 0417 · 4 marks · papermunch.org

Name ______________________________ Date ______________

Describe the difference between analogue data and digital data.[2]
Show answerHide answer
Analogue data is continuous and can take any value. Digital data has separate values and is stored as binary, 1s and 0s.
I got this one
Explain why an analogue-to-digital converter is needed when a sensor is connected to a computer.[2]
Show answerHide answer
The sensor produces analogue data. A computer can only process digital data, so the data must be converted first.
I got this one

Answers: Analogue and digital data

1. Analogue data is continuous and can take any value. Digital data has separate values and is stored as binary, 1s and 0s.
2. The sensor produces analogue data. A computer can only process digital data, so the data must be converted first.