Module 5 - Electroacoustics

Electroacoustics  ::  Electricity  ::  Filters  ::  Microphones  ::  Recording  ::  High-Fidelity Sound

Filters

This chapter builds upon the electrical principles you learned in chapter 18. Your home stereo system uses these principles to deliver the sound it does.

A filter is used to get rid of unwanted sound or certain frequencies. An amplifier takes a small amount of power and uses it to control a large amount of power. An oscillator is an electrical circuit that is unstable and causes it to produce electrical waves. An example of this is a audio generator that can be tuned to produce sound at a certain frequency. Electronic keyboards are full of oscillators.

In this chapter you will learn about filters, amplifiers, and oscillators and how they function. You will learn the basic electronic theory and formulas for them.

To successfully complete this chapter you should...

• Read chapter 19 in your text book (pages 383-392).
• Carefully study the important concepts about filters oscillators and amplifiers.
• Be able to name the different types of filters and their use.
• Given a diagram of a filter be able to determine if it is a low-pass filter or a high-pass filter.
• Given resistance and inductance, be able to determine the cutoff frequency of a filter.
• Given resistance and capacitance, be able to determine the cutoff frequency of a filter.
• Given a schematic diagram of an amplifier circuit, be able to find the voltage gain of the amplifier.

Important Concepts

Filters
high-pass
band-pass
band-reject
notch
cutoff frequency

Amplifiers
Transistors
PNP & NPN
Voltage gain
Current gain
Voltage amplifier
Power amplifier

Distortion in Amplifiers
Feedback
Operational Amplifiers
Oscillators
Function generators