In an operational amplifier, how does negative feedback influence the output signal in common applications such as amplifiers and filters?

Negative feedback in an op‑amp pulls the output toward a value that makes the difference between the two input terminals zero, so the amplifier behaves as if its gain were fixed by the feedback network rather than the transistor’s internal gain. In a voltage‑follower, the feedback forces the output to equal the input, giving unity gain and very low distortion. In a non‑inverting amplifier, the feedback resistor network sets the closed‑loop gain to a precise ratio, making the circuit insensitive to component variations. For filters, the feedback network shapes the transfer function, so a first‑order low‑pass filter can be built with a single resistor and capacitor while the op‑amp maintains the desired pole location. For example, a 10‑V input to a 1:10 amplifier with a 10 kΩ feedback and 1 kΩ input resistor yields a 10‑V output, showing the output is determined by the resistor ratio, not the op‑amp’s open‑loop gain.