The non-inverting amplifier is one of the most popular op-amp circuits similar to the op-amp inverting amplifier circuit. It provides a gain to the input signal without any change in the polarity. If a sine wave is fed to the input of this op-amp noninverting amplifier, the output will be an amplified sine wave with zero phase shift. Here the input is applied to the noninverting terminal of the op-amp. The noninverting amplifier gain is given by the expression A=1+Rf/Ri where Rf is the feedback resistance and Ri is the input resistance. The input impedance of a noninverting amplifier is extremely large, typically 100MΩ.
Non-Inverting Amplifier Circuit Diagram
- 741 Op amp
Working of Noninverting Amplifier
- The working of non-inverting amplifiers is similar to that of inverting amplifiers except that the output has no phase shift.
- The resistors Ri and Rf form a voltage divider network.
- Negative feedback is provided by applying a little of output voltage to the inverting input terminal through the potential divider network Ri and Rf.
- The voltage gain of the amplifier is determined by the ratios of Rf and Ri since Gain, A=1+Rf/Ri
- So the amplitude of the output voltage signal can be varied by varying either of the resistors Rf or Ri.
Gain of noninverting amplifier, A=1+ Rf/Ri
Let the gain be 11 so that the ratio Rf/Ri=10. Take Ri=1k and Rf=10k
Here we have demonstrated and explain how to build a non inverting amplifier circuit using op-amp 741.