Non inverting Amplifier

Non inverting Amplifier:

An amplifier which amplifies the input without producing any phase shift between input and output is called Non inverting Amplifier. The basic circuit diagram of a noninverting amplifier using op-amp is shown in the Fig. 2.20. The input is applied to the noninverting input terminal of the op-amp.

Non inverting Amplifier

Let us derive the expression for its closed loop voltage gain.

The node B is at potential Vin, hence the potential of point A is same as B which is Vin , from the concept of virtual share.

Non inverting Amplifier

From the output side we can write,

Non inverting Amplifier

At the inverting terminal,

Non inverting Amplifier

Entire current passes through R1 as input current of op-amp is zero.

Equating equations (2) and (3),

Non inverting Amplifier

Non inverting Amplifier

The positive sign indicates that there is no phase shift between input and output. The input and output waveforms are shown in the Fig. 2.21.

Non inverting Amplifier

The Table 2.2 provides the comparison of the ideal inverting and noninverting amplifier op-amp circuits.

Non inverting Amplifier