Hello friends! Today, we will discuss the operational amplifier, usually called an op-amp. It is one of the most useful building blocks in analog electronics, allowing us to amplify small signals, buffer a sensor, combine voltages and build active filters. The same basic symbol appears in many circuits, but its behavior depends strongly on the components connected around it. An op-amp responds to the voltage difference between two inputs. By feeding part of its output back to an input, we can obtain a predictable relationship between input and output. This feedback arrangement is the key to understanding practical amplifier circuits. We will start with the symbol and an ideal model, then introduce the limits of real devices. Along the way, we will calculate common amplifier gains and devel ...