Which of the following scenarios best illustrates the application of an operational amplifier in a circuit?

An operational amplifier is most clearly shown when it is used to amplify a small sensor signal so that it can be read by a microcontroller or used in further processing. In this case the op‑amp is configured as a voltage follower or unity‑gain buffer, which gives the sensor a low‑output‑impedance source and isolates it from the load. The op‑amp’s high open‑loop gain ensures that the output voltage follows the input voltage almost exactly, so a 10 mV change from the sensor becomes a 10 mV change at the output. For example, a thermistor that produces 0. 1 V when the temperature rises can be fed into a buffer op‑amp that outputs 0.