# 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 :

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

$\cfrac{V_{out}}{V_{in}}=G_V=-\cfrac{R_2}{R_1}$

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.

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.