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Inverting Amplifier

Inverting Amplifier

The inverting amplifier circuit is relatively a simple circuit. A resistor R_1 is placed between the inverting input and the input signal. A second resistor R_2 is place between the output of the op-amp and the inverting input. The non-inverting input will be tie to ground. You can find below the schematic for the inverting amplifier :

Inverting Amplifier Circuit

The closed-loop gain or voltage gain of the inverting amplifier can be found with this formula :


Below, you have an example of a 5V sine wave into the inverting input of a inverting amplifier with a gain (G_V) of -1. The positive supply is 5V and the negative supply is -5V.

Example of a 5V sine wave into an inverter amplifier with a gain of -1

Do note that if the positive supply or negative supply is not high or low enough, the output voltage will clip at Vs+ or Vs- if the amplify signal exceeds the supply voltage..

The input impedance of the inverting amplifier is Z_{in}=R_1. This is a small inconvenience since this will reduce the input impedance of the circuit and it will depends on R_1 . This could potentially cause issues if R_1 is too small.