# Output voltage of Class B Amplifier with global negative feedback

For the following schematic on the non-inverting input is applied a sine wave.

Shouldn't be the output on R19 0.9 out of the input voltage, by using a voltage divider between R31 and R19. From my simulation the input signal and output signal are exactly the same.

This amp is the final part of a simulation of an audio amplifier. Any help is appreciated, thank you. • No, because R31 (and R30) are inside the feedback loop. May 22, 2020 at 15:49
• Is there any formula which can tell me what is the maximum value of this resistances so that the output won't be clipped? May 22, 2020 at 16:07
• Basically, Ohms Law. May 22, 2020 at 16:08
• My max output is 9V, from this results that the current through my output resistance is 0.45 A, but from here I don't know how to continue, from OrCad if both of my resistances (R30 and R31) are 8 ohms or greater, the output signal gets clipped. May 22, 2020 at 16:10
• First get the Voh (max) and Vol(min) for your opamp at +/-15V from its datasheet.. Then subtract Vbe (Q3.Q4) from these. Now you have the peak output voltages available. Subtract your max output voltage to get V(R30,R31). You already have I(out) : the rest is Ohms Law. May 22, 2020 at 16:21