Chapter 5

Question 1

What does transduce mean?

Answer 1

To change energy from one from to another

Question 2

Give an example of transduction (cup and string)

Answer 2

When the person talks in the cup it is acoustic energy and changes to mechanical when the cup vibrates. the vibration travels up the string that travels to the next cup which vibrates and changes the mechanical energy to acoustic energy

Question 3

Why does the string must not be massive have to be pulled tightly?

Answer 3

Speech includes high-frequency energy so if the string is massive it will not vibrate well at high frequencies. If the string is compliant (loose) it will not vibrate well at high frequencies.

Question 4

How does a mic and speakers use transduction?

Answer 4

Microphones transduce acoustic energy into mechanical energy into electrical energy (called current).

A sound system amplifies electrical energy using transistors and a power source (ex battery, AC outlet)

speakers transduce electrical energy to mechanical energy to acoustic energy.

Question 5

Where is the acoustic energy transduced to mechanical energy on a mic?

Answer 5

at the diaphragm

in the cup example, it is the bottom of the cup

Question 6

What are the three ways mechanical energy of the diaphragm is transduced into electrical energy?

Answer 6

Dynamic mic
Ceramic mic
Electret mic

Question 7

Electromagnetic/dynamic microphones accomplish transduction. how?

Answer 7

moves a coil of wire in the vicinity of a magnet. It will alternately push and pull electrons movement in that coil

Question 8

How does transduction occur with ceramic microphones?

Answer 8

Transduction happens through piezoelectric (electricity from pressure). When two crystals are fastened together and then distorted, they give off a small electrical charge.
Pressure pushes the elections so that they are crowded and have a collective negative charge. negative charge repels electrons in the wire. releasing the pressure reverses the process

Question 9

How does an electret condenser mic transduce?

Answer 9

• This microphone uses
“capacitance” to transduce
energy from mechanical to
electrical:
• A relatively positively charged
diaphragm faces a
permanently negatively
charge back plate
• Movement of the diaphragm
will alternately attract
(opposites attract) and repel
electrons in a wire

Question 10

regardless of the design, what is the end result?

Answer 10

The end result is the diaphragm moving to and fro and, in turn, cause nearby air molecules to move to and fro to create a sound wave

Question 11

How does speech relate to transduction?

Answer 11

Electrochemical energy in the brain and neurons to the muscles of respiration and speech.

mechanical energy of the muscles of respiration and speech

sound waves (acoustic energy)

Question 12

how does transduction relate to hearing?

Answer 12

1. sound wave (acoustic)
2. mechanical energy at the middle ear
3. hydraulis energy in the inner ear (cochlea)
4. mechanical energy at the organ of Corti
5. electrochemical energy (neurotransmitter) from cochlear hair cells excite neurons