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lm386 audio amplifier circuit schematic

LM386 Audio Amplifier Circuit

The integrated chip LM386 is a low power audio frequency amplifier requiring a low level power supply (most often batteries). It comes in an 8-pin mini-DIP package. The IC is designed to deliver a voltage amplification of 20 without external add-on parts. But this voltage gain can be raised up to 200 (Vu = 200) by adding external parts.

Schematic of LM386 Audio Amplifier Circuit

lm386 audio amplifier circuit schematic

The external parts shown on diagram 3.1 can be selected to get the desired gain. Circuit A will give a voltage amplification of 200. Circuit B will give a gain around 50. The circuit C is not for voltage amplification but will raise the bass level by about 5 dB. Take note that the circuit C is to be connected between pins 1 and 5 of the IC.

Related Product: Audio Amplifier

The power output is around 550 mW at 16 ohm speaker impedance. This audio frequency amplifier is ideal for small battery powered devices.
If you use the external circuit A, replace the Rx with a jumper wire in the PCB.
If you use the external circuit C, solder the additional resistor and capacitor to the PCB points labeled Rt and Cy.

lm386 amplifier external parts

LM386 amplifier PCB and parts placement layout

lm386 amplifier pcb

30 Comments

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  • clyde

    can I use a 4 ohm 5W speaker

  • sukumar

    What is the reason for noise in this amplifier when I used a speaker of 4ohm I also connected a resistor of 10 ohm series with speaker

    • Boniface

      Don’t bother adding a 10 Ohm Resistor. This won’t hurt your amplifier.

    • Boniface

      You need to filter the Voltage aka adding a decoupling capacitor from Vcc to GND. Just add a 100uF 16V Polarized Capacitor from pin 6 to GND.

  • Dan

    what’s the values of C2 AND C3

    • apriljoslinggmail-com

      hello dan not sure if any1 got back to you about lm386 circuit.. i am new to electronics,but i have built this amp before. i used 0.1uf brown polly caps or you can use ceramic 104 or 222.
      didnt really want to answer as i feel i could be critasised for something as i am not a pro. just hummble beginner.

  • sagar

    is this LM386 amp will work for mic input signals ???
    means is it able to amplify mobile phone “micro phone” signal ???

    • Vishwas Deshpande

      Cellular phones have already inbuilt mic, preamp & low power amp. U simply connect audio out of ur cell phone to lm386 ckt. It will work out. In case of external mic signal, it needs to preamplify first & then fed to lm386 ckt. Just try out. cu…..

    • Erik

      Generally speaking, the LM386 is a power amp and requires a line level signal (e.g from the likes of an MP3 player or mobile phone output socket). Most microphone signals are too weak for LM386 on it’s own and require the signal to go through a preamp stage. I am unclear however how you intend to pass the microphone signal from your mobile phone and whether the phone has a microphone output which is already pre-amplified.

  • hameeda

    I need your help sir, what are the functions of all capacitors in this circuit. i am working on a project for school, and i need to mantion how the circuit works and the components functions

  • kitsof

    This is best lm386 amplifier schematic I’ve seen so far.Input ground (pin 2,7) is carefully separated from power ground (Vcc ,speaker) and they both meet at pin 4.Most of the schematics over the net miss that absolutely important point.The LM386 is very prone to various noises due to bad grounding.Well done!

  • rohitt rivedi

    how i connect 0.5w and 6ohm speaker (single) with usb.which ic is required

  • Abhishek

    can it drive single 4 ohm 5w speaker , if yes please send the circuit diagram for 5v supply (usb powered).

  • Toby

    Hi! I’m a little confuse about the input. Mostly jack come with 3 strings of wires. Can you give me an explanation how to connect those 3 wires or schematic diagram will do. Thanks!

    • standisher

      It is a mono amplifier. The ‘3 strings of wire’ you mention are on a stereo jack plug. If you plug a stereo device into this input you will only hear one channel of the output.

  • riery

    could this possibly be adapted to be a stereo headphone amplifier?

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