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I'm sorry I take what I said back, I thought it's OK to supply a negative voltage to any device by just swithcing the rails of the signal and problem is solved.

But it turned out that in other situations it won't work; like, most common case for me is to send the signal to a microcontroller when I searched about reading negative voltages by ADC unit in a microcontroller isn't possible.

So I must invert the negative signal by using another op-amp:

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Thanks to this YouTube tutorial: Using an Arduino to capture negative analog voltages.