# basic uses of operational amplifier

The primary use of the operational amplifier is as a small signal amplifier. By using feedback, operational amplifiers can be designed to have a wide range of gains. From the previous lab, it was shown that the op-amp draws very little current into its inputs. This means that the input impedance looking into the inverting and non-inverting inputs is very large. It was also seen that the open-loop gain was very large. Assuming the open-loop gain is infinity, we can show that the voltages at the inverting and noninverting terminals should be approximately the same at all times. Because of this, we say that the two terminals “track” each other. Based on these assumptions, a simple procedure for op-amp analysis can be formed.

Once an op-amp is integrated into a circuit, it can be easily analyzed through the following steps:

• Write the node equation at the inverting terminal.

• Write the node equation at the non-inverting terminal.

• Set the voltage at the inverting terminal equal to the voltage at the non-inverting terminal.

• Solve for the gain.