Microphone

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Quick Questions

Shade in the A or B circle for each question.

1. A microphone is an input device or an output device?

A Output device

B Input device

2. What does a microphone convert sound waves into?

A An electrical signal

B Light signals

3. Which part of a microphone moves when sound waves hit it?

A The diaphragm

B The ADC

4. What type of signal does a microphone first produce?

A Digital

B Analogue

5. Which device converts the microphone's analogue signal into digital data?

A Analogue-to-digital converter (ADC)

B Digital-to-analogue converter (DAC)

Match the Pairs

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

Left column		Right column
1microphone		AChanges the microphone's analogue electrical signal into digital data the computer can process
2ADC (analogue-to-digital converter)		Bsound waves -> diaphragm moves -> analogue signal
3Sound waves make the diaphragm move, and the microphone produces an analogue electrical signal		CThe microphone produces an analogue signal, not digital data. The ADC must convert the analogue signal to digital data afterwards.
4A microphone's analogue signal must be digitised before the computer can record a voice		Dmicrophone -> analogue signal -> ADC -> digital data -> computer
5A microphone is an output device that plays sound out loud		EAn input device that turns sound waves into an electrical signal the computer can use
6microphone -> digital data -> ADC -> computer		FA microphone is an input device that captures sound. It is a speaker that plays sound out loud as output.

Definitions

microphone

Fill in the Blanks

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

sound wave -> diaphragm -> ________ signal

analogue signal -> ADC -> _______ data

A microphone is an _____ device

// The _________ vibrates when sound hits it

voiceData ← ___(micSignal)

Spot the Error

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

Question 1

A OUTPUT sound FROM microphone

B signal ← ANALOGUE(sound)

C digital ← ADC(signal)

D STORE digital

Question 2

A IF voice_command = TRUE THEN

B sound ← SPEAKER()

C digital ← ADC(sound)

D ENDIF

Question 3

A sound ← MICROPHONE()

B signal ← ANALOGUE(sound)

C digital ← ADC(signal)

D SEND signal TO computer

Question 4

A WHILE recording = TRUE

B signal ← MICROPHONE()

C digital ← ADC(signal)

D ENDIF

Question 5

A command ← MICROPHONE()

B digital ← ADC(command)

C IF digital = 'lights on'

D TURN_ON light

Answer Key

Microphone

Section A: Quick Questions

B — Input device

A — An electrical signal

A — The diaphragm

B — Analogue

A — Analogue-to-digital converter (ADC)

Section B: Match the Pairs

microphone → An input device that turns sound waves into an electrical signal the computer can use

ADC (analogue-to-digital converter) → Changes the microphone's analogue electrical signal into digital data the computer can process

Sound waves make the diaphragm move, and the microphone produces an analogue electrical signal → sound waves -> diaphragm moves -> analogue signal

A microphone's analogue signal must be digitised before the computer can record a voice → microphone -> analogue signal -> ADC -> digital data -> computer

A microphone is an output device that plays sound out loud → A microphone is an input device that captures sound. It is a speaker that plays sound out loud as output.

microphone -> digital data -> ADC -> computer → The microphone produces an analogue signal, not digital data. The ADC must convert the analogue signal to digital data afterwards.

Section C: Definitions

microphone — An input device that turns sound waves into an analogue electrical signal, which an ADC converts to digital data so the computer can record or process voice.

Section D: Fill in the Blanks

sound wave -> diaphragm -> analogue signal

analogue signal -> ADC -> digital data

A microphone is an input device

// The diaphragm vibrates when sound hits it

voiceData ← ADC(micSignal)

Section E: Spot the Error

A — A microphone is an input device, so the sound must be taken in with INPUT, not sent out with OUTPUT. The line should be INPUT sound FROM microphone.

B — A speaker is an output device that plays sound. To capture a voice command you need the input device, so the line should be sound ← MICROPHONE().

D — The analogue signal must first be converted by the ADC. The computer can only process the digital data, so the line should be SEND digital TO computer.

D — A WHILE loop must be closed with ENDWHILE, not ENDIF. The last line should be ENDWHILE.

C — The IF statement is missing the keyword THEN. The voice command check should read IF digital = 'lights on' THEN.