For the following LM386 amp i have a couple of questions.
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Is C3 and R1 a low pass filter and if so how do i calculate the cutoff frequency for it? I.e. do i have to take the impedance of C2 into consideration?
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What does the capacitor C2 do. When diagram one states that it removes the dc component, is this like it removing the bias? Also C2 with R1 and C3 make a high pass filter doesnt it? If so how do i calculate the cutoff frequency for it?
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For the input voltage into the amp, say if it was a square wave from 0-5V, doesnt a high pass capacitor have to be used to remove the dc bias with a voltage divider so that Vin is 0.4 to -0.4v? If this high pass filter is used to remove the dc bias is C2 needed then? Diagram 3 shows this dc bias remover.
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If the speaker has a max power of 0.25W and a resistance of 8ohms, does this mean i need a 1.41 V output from the amp (V=sqrt(PR))
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If i need a lowpass filter that removes say 15Khz as the cutoff frequency can i just change the values of C3 and R1 to get this cutoff?
Thanks for helping in advance
Note 1st diagram is just something i found online stating what potentially each C2 etc is.
Datasheet for LM386: http://www.ti.com/lit/ds/symlink/lm386.pdf
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