Audioguru
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Your amplifier works when you press on it because a connection is bad or missing,
You are confused because the speaker is wrongly marked + and - instead of A and B.
The speaker is a small coil of wire with one end connected to ground (0VDC) and the other end is driven with AC (with no DC) from the capacitor.
The output pin of the LM386 amplifier is at half the positive DC power supply voltage so that audio can swing it up and down. The capacitor blocks the DC but passes the AC audio.
Therefore the + wire of the capacitor connects to the LM386 and the - wire of the capacitor connects to the speaker.
Ok, so, as I told Audioguru, the transistor and polarized capacitors are backwards. If so, why I managed to get sound from it? shouldn't it be complettly silent? or blown up or something? haha.To avoid any doubt here is the pin order on that transistor
View attachment 165432
According to the data sheet, it is a symetrical FET, that means the source (S) and drain (D) pins are interchangeable but the gate certainly isn't.
I didn't mean to permanently remove the transistor stage, just to isolate the problem by injecting the signal after it instead of before it. As it doesn't provide any amplification, the volume should be about the same.
Brian.
I see a couple of mistakes on your drawing.
The wires to the jack are the wrong way around.
And you have power going through the led, + should go to the led and the board, and the resistor side of the led should go to ground, this is most likely the cause of the tic toc tac.
The ground connections you've shown look correct.
All set and working propperly! Thank you everybody for your help! I will keep practicing!Now you have the entire amplifier powered from the low voltage and low current from the LED instead of directly from the from the battery and its switch.
You said earlier that you have a voltmeter. Then please use it to measure and report to us:
1) The battery voltage when it powers the amplifier and brightly lights the LED with its series resistor.
2) The S pin of the Jfet.
3) The output pin 5 of the LM386 when it has no sounds.
Of course the ground pin of the volume control must connect to ground. If it doesn't then the volume would be at full blast all the time.
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