I am currently putting together a simple audio amplifier using an LM386 chip. In the midst of studying how this chip works, and the proper circuit analysis behind it, I began thinking about how conventional current would flow in this particular case.
I understand that there is an audio input that produces an AC waveform across the copper into the LM386 chip. There is also a Direct Electric current flowing from a battery into the LM386 chip - utilized for amplification.
It is when these two signals meet that confuses me... The DC current flows with the Audio Waveform on the output of the chip. Based on the picture of the circuit below, I noticed that there are two capacitors, one a high pass and the other a low pass.
From what I have gathered, the capacitors are there to block the DC current, but allow the Audio AC waveform to pass through - clipping waves too high or too low.
What I want to know - how does the DC current boost an alternating waveform if the DC current is only pushing in one direction? When the wave would push one way I would think there would be more power (flows with the current), but then when it pushed the other way, wouldn't it flow up stream?
What does this look like prior to hitting the capacitors? Would the DC current be in a wave pattern, or would it still be a line with the audio waveform alternating around it? I would assume that there would be a solid line of DC flow at a voltage level, with the Audio waveform alternating back and forth with the DC voltage at its mid-point.
Finally, I assume when the capacitors are removed you hear that electric hum... But with the capacitors there, would it not muffle the amplification?
It is a bit of a noob question, and unfortunately I am in the midst of getting an Oscilloscope, but do not have one yet.
I'd appreciate any help on this! Thank you.