Inverting Op Amp

Inverting Operational Amplifier - Inverting Op Amp 

Inverting Operational Amplifier - Inverting Op Amp

This type of op-amp circuit produces an output which is 180° out of phase with its input.To explain this, let us again think of the virtual zero point at the inputs of the operational amplifier. If we now apply a voltage V_IN to the input, a current I₁ must inevitably flow:

Since the input resistance of the operational amplifier is very high, the input current of the OPV must also be negligibly low. This means that the current I₁ must flow via R₂.

Combining both equations, taking into account the direction of the current and you get:

Exercises - Inverting Op Amp

Op-Amp as Inverting Amplifier - Exercise

Exercise 1:

R1 = 2 kΩ, R2 = 22 kΩ, V_IN = 1 V

1. What voltage is measured between the inverting and the non-inverting input in the steady state ?
2. At what potential is the inverting input in the steady state ?
3. Calculate the current flowing through R2 ?

Exercise 2:

R1 = 20 kΩ, R2 = 200 kΩ, U_IN = -1 V

1. What is the output voltage V_OUT ?
2. Which statement is true?
   IR1 < IR2
   IR1 = IR2
   IR1 = 10-I_R2
3. What current flows through R1 ?