By : Arbaz KhanBEES/S14/0234Basic Elec- LAB

Audio AmplifierPROJECT REPORT

Audio Amplifier: An audio amplifier is an electronic amplifier that amplifies

low-power audio signals (signals composed primarily of frequencies between 20 - 20 000 Hz, the human range of

hearing) to a level suitable for driving loudspeakers and is the final stage in a typical audio playback chain.

Objective: The main objective of this is to understand the working

of amplifiers.

Purpose: The purpose of this project is to understand the need

and working of amplifiers.

Description: Before we go into the depth of our project, we first

need to understand what is an amplifier and why do we need it?

An amplifier is a device for increasing the power of a signal by use of an external energy source. In an electronic amplifier, the input "signal" is usually a voltage or a current. Other types exist; a fluidic amplifier increases the power of signals represented as flow of as or liquid, for example. Amplifiers may be classified in a variety of ways depending on their application, the frequency range they cover, or the active devices used. Ideally an amplifier increases the power of a signal without otherwise altering it; practical amplifiers have finite distortion and noise which they invariably add to the signal.

The quality of an amplifier can be characterized by a number of specifications, listed below.

1.     The gain of an amplifier is the ratio of output to input power or amplitude, and is usually measured in

decibels. (When measured in decibels it is logarithmically related to the power ratio: G(dB)=10

log(Pout /(Pin)). RF amplifiers are often specified in terms of the maximum power gain obtainable, while

the voltage gain of audio amplifiers and instrumentation amplifiers will be more often Gain

specified (since the amplifier's input impedance will often be much higher than the source impedance, and the load impedance higher than the amplifier's output impedance). For example, an audio amplifier with a gain given as 20 dB will have a voltage gain of ten (but a power gain of 100 would only occur in the event the input and output impedances were identical).

Order of Priority Ground Plane Decoupling Placement and Connection EMC Circuit Placement and Connection Input and Analog Control Routing

Ground Plane (Cont’d) Use ground plane to connect all critical

circuits This minimizes ground impedance,

especially

Ground Plane (Cont’d) Place the IC at the center of the ground plane

and ground the PowerPAD Ground decoupling caps and EMC

components to the PowerPAD area through ground plane.

Place inputs on one side of the circuit and power and outputs on another to separate the currents.

This approach minimizes interference that could reduce audio quality and makes decoupling and EMC filters and snubers work best.

Poor vs. Proper Decoupling

EMC Filtering (cont’d) Place EMC snubbers& filters very near the IC. Ground through ground plane & connect

outputs to cap pads, directly or through broad copper, & not to inductors, to minimize stray inductance

Place EMC filter caps as close to the IC as possible on the ground plane layer and ground them to the IC through the ground plane

EMC Filtering (cont’d) This approach minimizes unfiltered loops

and trace lengths as well as stray inductance.

This makes EMC components function best & gives the widest possible filter bandwidth.

Poor vs. Proper Filter Placement

Circuit Diagram

Thank YouFor your attention