I would like to know why a non-inverting input op-amp is used and why not an inverting op-amp?
Why do we need a feedback loop?
Also why is that the gain is determined by the ratio of the two resistors forming the divider bridge at the output of the OpAmp?
Also what are the specific uses of the capacitors and resistors used?
I find the feedback loop to be confusing. Wouldn't C3 somehow affect AC gain?
Thanks alot. Can I use the above circiut to drive a small speaker? Which is 0.5 W and 8ohms?
You mean use the circuit to amplify the signal from the microphone and drive a speaker? You can try it, but it won't be very loud. The LM358 is a low-power op amp so it is only designed to source or sink a few milliamps.
What I want to achieve is that, I want to connect the output from microphone to arduino and from arduino to speaker. So when I scream or whisper the microprocessor will detect the voltage and print out for me on the computer using serial monitor. And if the voltage is higher than a certain value it will on the speaker and output the voice. So, to achieve this I am using an electret microphone, a speaker with 8ohms and 0.5W and arduino Uno. I would like to know how and what I I should do to achieve this?
Can I have a block diagram for this statement: You could use the op amp circuit to amplify the signal for the Arduino. You could use the second of the two chips I linked to, to amplify the output of the op amp and feed the speaker. That chip has a DC volume control input with a mute mode, which you can drive from an Arduino pin via a pot (for volume control). A low on the pin will mute the output, a high will enable the output with volume controlled by the pot.
About the diagram. I want the voice from microphone to go arduino and check the frequency or voltage range and if its between a certain range to on the speaker and output from the voice from the speaker. Is it possible with the block diagram you mentioned.