Attached is the circuit for the wonderful Mini-Audio Amplifier product from Radio Shack: RS product 062620.
I am trying to put a similar amplifier on my circuit board, but am running into terrible feedback at stability issues. I would like to understand this circuit better, but am confused about a few things:
1) Pins 1 and 8 are supposed to set the gain on the LM386. Why does this amplifier have a capacitor between 1 and 5? I have used the LM386 before, but only in it's default state (20x, nothing b/w pins 1 and 8).
2) What is the purpose of the NPN before the input of the LM386? I am trying to get better at analyzing these circuits, but would love some pointers on where to start. Is it a pre-amp? What is the gain? Why is this transistor even needed?
Thanks so much.
Greg
I am trying to put a similar amplifier on my circuit board, but am running into terrible feedback at stability issues. I would like to understand this circuit better, but am confused about a few things:
1) Pins 1 and 8 are supposed to set the gain on the LM386. Why does this amplifier have a capacitor between 1 and 5? I have used the LM386 before, but only in it's default state (20x, nothing b/w pins 1 and 8).
2) What is the purpose of the NPN before the input of the LM386? I am trying to get better at analyzing these circuits, but would love some pointers on where to start. Is it a pre-amp? What is the gain? Why is this transistor even needed?
Thanks so much.
Greg
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