Speaker

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. What type of device is a speaker?

A An input device

B An output device

2. What does a speaker turn an electrical signal into?

A Sound waves

B Light waves

3. Which part of a speaker vibrates to make the sound waves?

A The lens

B The cone

4. What makes the speaker cone move?

A An electromagnet

B A laser beam

5. Digital sound from a computer must be converted before a speaker can use it. Which converter does this?

A Digital-to-analogue converter (DAC)

B Analogue-to-digital converter (ADC)

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1speaker.play(signal)		AThe speaker cone moves back and forth, pushing the air to make sound waves
2cone.vibrate()		Banalogue = DAC(digitalSound)
3A digital-to-analogue converter (DAC) changes stored digital sound into an analogue signal before it reaches the speaker		CThe speaker takes an electrical signal and turns it into sound waves that we can hear
4An electromagnet in the speaker moves the cone when the electrical signal flows through it		DThe speaker is sent digital data directly. It needs an analogue signal, so a DAC must convert the digital sound first.
5speaker.play(digitalSound)		EA speaker is an output device that produces sound. A microphone is the input device that records sound.
6speaker = input device that records sound		Felectromagnet.move(cone, analogue)

Definitions

speaker

Fill in the Blanks

Complete each line of code by filling in the missing parts.

A speaker is an ______ device

Digital sound -> ___ -> analogue signal

An _____________ moves the cone

Cone vibrations make sound _____

Uses: music, alerts and _____ output

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A digital ← READ_FILE(song)

B signal ← DAC(digital)

C SEND signal TO speaker

D electromagnet MOVES screen

Question 2

A signal ← DAC(digital_sound)

B SEND signal TO speaker

C cone STAYS STILL

D OUTPUT sound_waves

Question 3

A signal ← ADC(digital_sound)

B electromagnet ← ON(signal)

C cone VIBRATES

D OUTPUT sound_waves

Question 4

A INPUT alert_sound

B analogue ← COPY(alert_sound)

C SEND analogue TO speaker

D OUTPUT beep

Question 5

A speaker.type ← "input"

B speaker.part ← "cone"

C speaker.makes ← "sound"

Answer Key

Speaker

Section A: Quick Questions

B — An output device

A — Sound waves

B — The cone

A — An electromagnet

A — Digital-to-analogue converter (DAC)

Section B: Match the Pairs

speaker.play(signal) → The speaker takes an electrical signal and turns it into sound waves that we can hear

cone.vibrate() → The speaker cone moves back and forth, pushing the air to make sound waves

A digital-to-analogue converter (DAC) changes stored digital sound into an analogue signal before it reaches the speaker → analogue = DAC(digitalSound)

An electromagnet in the speaker moves the cone when the electrical signal flows through it → electromagnet.move(cone, analogue)

speaker.play(digitalSound) → The speaker is sent digital data directly. It needs an analogue signal, so a DAC must convert the digital sound first.

speaker = input device that records sound → A speaker is an output device that produces sound. A microphone is the input device that records sound.

Section C: Definitions

speaker — An output device that turns an electrical signal into sound. An electromagnet makes a cone vibrate, and the vibrations make sound waves. A DAC first converts digital sound to analogue.

Section D: Fill in the Blanks

A speaker is an output device

Digital sound -> DAC -> analogue signal

An electromagnet moves the cone

Cone vibrations make sound waves

Uses: music, alerts and voice output

Section E: Spot the Error

D — In a speaker the electromagnet moves the cone, not a screen. The line should be: electromagnet MOVES cone.

C — The cone has to vibrate to make sound waves. If it stayed still there would be no sound. It should be: cone VIBRATES.

A — A DAC (digital-to-analogue converter) is needed here. An ADC converts analogue to digital, which is the wrong direction. It should be DAC.

B — Copying the data does not convert it. The digital alert sound must go through a DAC to become an analogue signal. It should be: analogue ← DAC(alert_sound).

A — A speaker is an output device because it sends sound out to the user. It should be: speaker.type ← "output".