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One Basic Opamp Question- the point of using an inverting amplifier in a circuit

HARI T O1
Expert 1375 points

Dear Team,

This may be a simple question to most of you, but I'm having trouble understanding the concept behind the use of an inverting amplifier. What is the purpose of using an op-amp in an inverting amplifier if all of the current flows through the feedback resistor?

This is confusing me for a long time. What actually opamp is doing here.

Regards

HARI

  • 0
    Guru 280610 points

    The output current of the opamp flows not only through the feedback resistor, but also into or out of the load connected to Vout. The opamp supplies as much current as needed to keep Vout at the correct voltage.

  • 0
    Guru 140200 points

    Hi Hari,

    the inverting OPAmp forces the -input to virtual ground (0V). By this the OPAmp is not plagued with common mode voltage issues. So the distortion is much less when there is no common mode voltage induced distortion (due to finite and nonlinear common mode rejection).

    Another advantage is when using the OPAmp as a TIA. Forcing the -input to virtual ground (0V) then means that a detector must not charge any stray capacitance or even cable capacitance. So it does not come to a voltage dividing caused by these capacitances.

    Kai