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  • 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.

    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

    
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    17 Responses to "LM386 Audio Amplifier Circuit"

    1. can it drive 0.5W, 4 ohm speaker

    2. yes, it should be able to drive any single 0.5 watt speaker, but I would add a 10-ohm resistor in series with speaker for safety because the chip is designed for a 16-ohm speaker. I am using am 8-ohm 0.6 watt speaker with a 10-ohm resistor on mine.

    3. Sandy kashyap says: on July 18, 2012 at 2:35 pm

      I m sandy ,can any one tell that what is the use of IC LM386 in multi tone siren ? thaks

      • Jim Keith Jim Keith says: on July 18, 2012 at 4:44 pm

        Hi Sandy,
        The LM386 is an audio power amp IC that applies much like an operational amplifier. As such, it can be configured as a power oscillator in a siren. Adding switches or clever circuitry makes it multi-tone. Unfortunately, I do not have a schematic.

        Jim

    4. Am I correct in assuming that I can use any value for C1 between 47 and 100 mic, and for C4, any value between 220 and 470 mic? Also if I want to add bass boost AND a gain of 50, do I need to modify either circuit B or C when applying them to the main circuit? Thanks for your help.

    5. how values of capacitor and resistor are calculated in the ckt of amplifier?

    6. can you link multiple of these in parallel and will it work for 1.5 watt speakers?

    7. I want to construct an amplifier and connect it to two tweeters 200W each and the input is coming from an mp3 player any suggestion ???

    8. Can i use this circuit for 10w 4 ohm speakers?

    9. for the transformer… 220 v – how many amperes?

    10. hi.. can i ask if this diagram is 100% on when done?.. cause i wanna try this diagram for my school project.

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

    12. 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 says: on January 14, 2015 at 6:27 pm

        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.

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

    14. rohitt rivedi says: on February 12, 2015 at 9:16 am

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

    15. 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!

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