Good morning, I'm new and I hope I posted in the right place.

I should make a circuit that compares a differential voltage and has 3 outputs:
+5V (or +3.3V) when the input difference is Greater of 50mV
-5V (or -3.3V) when the input difference in lower than -50mV
0V (or a very close to zero voltage) when the input difference is between -50mV and 50mV

How can I make it using commercially available components?

 

See

 

Thank you.

But I have a problem: my in voltage signal is differential; it is from two wires and not from a wire and the ground.

I'm not very good with analog electronics and I do not know how to adapt this circuit in a case where I have a dual signal (between two wires).

 

Use a pre-differential amplifier. The signal received from it is fed to the input of my circuit.
In the textbooks you will find many schemes of differential amplifiers built on operational amplifiers. I gave you the basis of the decision.