Question

Define an inverting amplifier circuit and calculate its gain.

Answer 1

An inverting amplifier is a basic electronic circuit configuration used to amplify an input signal while inverting its polarity (i.e., the output signal is 180 degrees out of phase with the input signal). It consists of an operational amplifier (op-amp) and two resistors. The op-amp has a high input impedance and a low output impedance, which makes it suitable for amplification purposes.

The basic schematic of an inverting amplifier is as follows:

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    Vin ---- R1 ----+---- Vout
                    |
                   R2
                    |
                  ----
                  |
                 GND


Where:

Vin is the input voltage.
Vout is the output voltage.
R1 is the feedback resistor connected between the op-amp's output and its inverting input terminal.
R2 is the input resistor connected between the inverting input terminal and the ground (GND) reference.

The gain (A) of an inverting amplifier is given by the formula:

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A = -R2 / R1


The negative sign indicates the inversion of the input signal. The magnitude of the gain is determined by the ratio of the resistance values of R2 and R1. This means that the output voltage will be the input voltage multiplied by the gain (with inversion).

Please note that the gain formula assumes ideal conditions and does not take into account the effects of op-amp bandwidth, input impedance, output impedance, and other non-ideal characteristics. Additionally, the values of the resistors should be chosen carefully to ensure stability and proper functioning of the circuit.