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Topic: Building an Audio Analyzer with Matrices and Mega2560 / Uno and FFT and Op amps (Read 4 times) previous topic - next topic

dhenry

Quote
I know how to get a gain lower, using negative feedback.


Again, name your favorite opamp and I can show you how to get its open loop gain down to 1x (or any number you wish to have).

No negative feedback. How's that?

All you need to do is to  name your favorite opamp.

Magician


dhenry

Again, just name your favorite opamp and I can show its gain < 1x (or 200x if you prefer), without using negative feedback.

Does that make your favorite opamp not an opamp?

Papa G

Okay, I'll play, configure a 741 op-amp for a DC open loop gain of 1 with no external components.

The LM386 is not an op-amp. It is a PGA at best.

Aaron_dyer

Ok damn guys....this isn't a see who pees farther contest...

I'm an Electronics Engineer as well.

I will say my favorite op amp to use is the LM358 but if I'm using one for multiple I/Os, I would use the LM3900.....However since I'm trying to tackle my original question.....using FFT to calculate a good audio analyzer output interfaced by the arduino...I know its possible and using the LM386 (Low power audio Amp) is what I have in mind.....

I hate op amps that need that negative supply i.e.  741 

I just don't want negative gain I know that much so interfacing either amp via its non -inverting input  (Rf / Ri) + 1 = Av (Gain) 

now interfacing its output to the arduino via an analog Input and then interfacing that to maybe some LED drivers (Max7219s) to drive LED matrices......

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