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Audio amplifier

Summary

By: 
Himanshu Choudhary

In several cases the sound generated is not clearly audible and hence it is required to increase the intensity level so that it can be further used. This audio amplifier circuit diagram based project demonstrates the principle and operation of a simple sound amplifier. The circuit is divided into three parts:

1.Sensor,

2.Amplifier, and

3. Output.

Sensor converts the physical characteristics of sound into electrical pulses, which is amplified by the amplifier unit.

The amplified output is obtained across the speaker. This circuit finds applications in security systems and as intermediate circuit to sense/amplify sound signals.

 

Description

 

The audio amplifier circuit diagram is based on condenser mic which is used as a sensor to sense the audio signals and convert them to electrical pulses. The output of the mic is passed to Transistor T1 through a capacitor C1. The purpose of capacitor C1 is to block the DC components. Resistor

 

R1 is used to provide the necessary biasing to the condenser microphone. Transistor T1 is used in the collector to base biasing configuration. This is achieved through resistance R2, which provides negative feedback to the base of T1. The output of T1 appears across R3, which is the input to T2. The necessary filtering is provided by the capacitor C2. Transistor T2 is biased in the fixed bias configuration. The base is biased by the resistor R4. The output of T2 appears across the load resistor R5. The capacitor C3 helps in filtering the noise at the output end. The output appears across an 8, ½ watt speaker.

 

 

Circuit Diagram

Components

Resistor Image
Resistor

Resistor is a passive component used to control current in a circuit. Its resistance is given by the ratio of voltage applied across its terminals to the current passing through it. Thus a particular value of resistor, for fixed voltage, limits the current through it. They are omnipresent in electronic circuits.

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Capacitor image
Capacitor

 

 

Capacitor is a passive component used to store charge. The charge (q) stored in a capacitor is the product of its capacitance (C) value and the voltage (V) applied to it. Capacitors offer infinite reactance to zero frequency so they are used for blocking DC components or bypassing the AC signals. The capacitor undergoes through a recursive cycl...

BC547 | Transistor BC547  | PDF Datasheet
Transistor BC547
BC547 is an NPN bi-polar junction transistor. A transistor, stands for transfer of resistance, is commonly used to amplify current. A small current at its base controls a larger current...
Condenser Microphone, Condenser Mic Image
Condenser Microphone
 
Condenser microphone (mic) is a transducer that uses a capacitor (or condenser) to convert acoustical energy into electrical energy. The sound waves result into electric...
Speaker Image
Speaker
A loudspeaker (or "speaker") is a transducer that converts electrical energy into acoustical energy. When an electric signal is applied to the input pin of speaker, it generates sound waves. The other pin is connected to ground. A speaker is commonly used to produce sound in response to a sensor output. For example, in an...
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