What Is A Non-Inverting Amplifier

What Is A Non-Inverting Op-Amp?

A non-inverting op-amp (operational amplifier) is a circuit that gives an output voltage in phase with the input voltage.
The simple way to understand is, if the input pulse is positive, then the output is also positive.
Now let’s understand the operation of the non-inverting amplifier below.

Here the input signal which is to be amplified is applied to the non-inverting (+) terminal of the Op-Amp.
The resistor R1 is connected to the inverting (-) pin of the opamp and the other terminal is connected to the ground and other resistor is the feedback resistor (Rf) is connected between the output and inverting (-) pins of the op-amp.
The detailed connection diagram of the non-inverting amplifier is shown in Fig.

The input and output waveforms of the non-inverting op-amp are shown in the below figure.
These waveforms are created by assuming that the amplifier’s gain and a sine wave are used as input signals.
From these waveforms, it’s evident that the output is twice the size of the input, like Vout = Av * Vin, and it is in phase to the input.

As we know for the ideal Op-Amp Input Impedance Ri=∞ there the current flowing from both input terminals is zero (I1 = I2 = 0).

From the above figure, we can write that,

$$V2\;=\;\frac{R1}{(Rf+R1)}\;*Vo$$

As per the virtual short concept

$$V2\;=\:Vs$$

$$Vs\;=\;\frac{R1}{(Rf+R1)}\;*Vo$$

$$Av\;=\;\frac{Vo}{Vs}\;=\;\frac{R1+Rf}{R1}$$

The final equation for the voltage gain of the inverting amplifier is,

$$Av\;=\;1+\frac{Rf}{R1}$$

It has a very high input impedance
The gain factor is exceptionally high.
The output of this op-amp is in phase with the input signal.
Non-inverting op-amps generally do not attenuate the input signal, ensuring that the output signal retains its original magnitude.
Non-inverting configurations are less sensitive to noise present in the input signal, resulting in an improved signal-to-noise ratio at the output.