Simple LM386 Based Audio Amplifier circuit designed by using IC LM386 From Texas Instruments. It is basically power amplifier designed for use in low voltage supply this circuit operates with 6 Volts supply. Here the amplifier circuitry amplifies the audio signal this signal fed to the input of the speaker which it convert into sound output. Audio frequency range lies in the frequency range of 20Hz-20KHz.
LM386, LM386M-1 and LM386MX-1 are power amplifiers designed by Texas Instruments for to use in low voltage consumer applications. This IC designed to give output gain from 20 to 200 dB. IC LM386 comes in PDIP, SOIC and VSSOP packages. Due to its wide supply voltage range (4V to 18V) it can be used in different levels of applications.
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Construction and Working
The LM386 Based Audio Amplifier is built around an 8-ohms,one -watt speaker (LS1), four capacitor and few other components. A 6V battery is used to power this circuit. Here Four electrolytic capacitor are used in this circuit. C1 is connected to the middle terminal of 10K potentiometer VR1. C2 is connected to pin 1 and 8 of IC1. Pin 5 of IC1 is output terminal, which is connected to speaker LS1 through C3. C4 is connected to the positive term of 6V battery and ground. Positive side of 6V is connected to pin 6 of Ic1 and the other side to ground terminal to pin 4.
Inverting pin 2 of IC1 is connected to ground and Non-inverting pin 3 is connected to the input terminal through VR1. Audio input is fed to CON 1. VR1 is used to control volume. switch on S1 and keep VR1 to its mid position. You can check the operation of amplifier by touching on input terminal pin 3 of IC1 and you should hear a noise sound from the speaker.