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I have a simple question.

I'm making an audio amplifier using the circuit given in the LM386 datasheet. According to the sheet, my IC can supply max 1W of output power and recommend load is 4 ohm.

The problem is I have a 4 ohm 10W speaker.

Does the 10W rating of speaker mean that it can take maximum 10W (meaning it will work fine with lower power as well) or that it will try to extract full 10W from the IC and in doing so damage it?

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  • \$\begingroup\$ I don't know the circuit you're considering, but you really really can't drive a 4Ω speaker with an LM386 to any level of satisfaction. Typically, when you buy a 4Ω speaker these days, it's because you want a good fidelity of the sound coming out of it. The LM386 is completely the wrong chip for that. It's simply a relatively bad amplifier. \$\endgroup\$
    – Marcus Müller
    Commented Apr 10, 2021 at 10:43
  • \$\begingroup\$ It's given in the datasheet that the recommended speaker impedance os 4 ohm. Besides I don't care about the quality, I just want to know that 10W speaker will kill the IC or not, read the post again. \$\endgroup\$
    – knight
    Commented Apr 10, 2021 at 10:45
  • \$\begingroup\$ If you don't care about the audio quality, just don't attach your speaker to the amplifier - sure, it doesn't make any sound that way, but that's just 100% distortion, which you don't care about. You'll need to read the datasheet closer: you can drive 4Ω, with a high supply voltage (which you probably can't use), and with low output volume. Again, it's plain the wrong IC for the job. There's many different LM386 on the market, and the cheaper ones (which you probably have one of) might have less thermal and output short protection – which is exactly what you're asking about. We can't tell you, \$\endgroup\$
    – Marcus Müller
    Commented Apr 10, 2021 at 10:50
  • \$\begingroup\$ since you're not telling us which exact make and model of the LM386 you have! \$\endgroup\$
    – Marcus Müller
    Commented Apr 10, 2021 at 10:51
  • \$\begingroup\$ LM386N-4 is the exact make... \$\endgroup\$
    – knight
    Commented Apr 10, 2021 at 10:59

2 Answers 2

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You don't have a problem. You can connect a speaker that can handle 10W to an LM386 which can only output 1W.

The speaker is rated 4 ohms which is compatible with the 4 ohm recommendation of the LM386 you use.

The speaker power rating will not be exceeded by the LM386.

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    \$\begingroup\$ Thanks bro🙏🙏...i was building the circuit for prototype purposes. Later will use better quality amplifier IC. \$\endgroup\$
    – knight
    Commented Apr 10, 2021 at 11:09
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Ohms law has the answer. Put simply, the speaker will only take what you give it. Just don't give it more than 10W.

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  • \$\begingroup\$ Thank you bro!!! \$\endgroup\$
    – knight
    Commented Apr 10, 2021 at 11:10

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