audiolm386
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?
Filter the signal before the amplifier, not after it.
If you overdrive the signal, it will be distorted.
LM386 is good when you don't much care about audio quality or power or efficiency. If you do care about any of those things there are modern parts that do a lot better.
The LM386 amplifier's inputs are an internally biased differential pair, with common mode input range extending to the indicated ground, Vee, or actually 0.4 Volts below ground.
In order to not disturb this internal biasing, the input signal must be capacitively coupled (or perfectly ground-referenced) - a capacitor in series on the input line is needed.
Next, for a voltage gain of 200, the input signal peak to peak needs to be under 1/200 of the output voltage range of the amp. While I could not find this specified in a quick scan of the datasheet, if we assume 7 volts output voltage range with a 9 Volt supply, the input signal needs to be under 35 mV peak to peak, to avoid clipping the signal. Clipping would result in mild to severe distortion of the output - though this does not explain the complete lack of signal you find on output.
If the incoming signal is higher than this 35 mV P-P, a potentiometer as an attenuator on the input is suggested.
Once these fixes are done, please revert with results, so the answer can be added to if needed.
Best Answer
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.