ECE Projects
 
 

 

Electronic Projects

       AudioRF Circuits 
     
      Event Detection Circuits 
         
      Math Function Circuits 
         
      Measurement Circuits 
    
      Motor Control Circuits 
         
      Power Supply Circuits 
         
      Sensing Circuits 
         
      Special Function Circuits 
         
      Switching Circuits 
     
      Timing Circuits 
         
      ToneWave Generators 

Audio Amplifier Circuit

Figure 1.  Audio Amplifier Circuit Diagram

 This circuit is an audio amplifier consisting of two stages of amplification.  The 741 operational amplifier is used as a pre-amplifier whose gain is controlled by its feedback resistor R2.  The 386 is a general-purpose power amplifier used as the output driver for delivering power to the speaker.  The volume of the speaker may be controlled via resistor R3.  A 0.1 µF bypass capacitor must be placed across the power supply to reduce the noise.  The value of R2 must be chosen well to prevent oscillation or distortion