Question

Define an inverting amplifier configuration.

Answer 1

An inverting amplifier is a basic electronic circuit configuration used to amplify an input signal while inverting its polarity (i.e., flipping the sign). It is commonly built using an operational amplifier (op-amp) as the active component. The key characteristic of an inverting amplifier is that the output voltage is proportional to the negative of the input voltage.

The basic schematic of an inverting amplifier consists of an op-amp with two resistors: a feedback resistor (Rf) and an input resistor (Rin). The input signal is applied to the inverting terminal (usually labeled as "-" or "IN-") of the op-amp, and the output is taken from the output terminal (usually labeled as "OUT"). The non-inverting terminal (usually labeled as "+" or "IN+") is typically connected to a fixed voltage reference, like ground (0V).

Here's the general schematic of an inverting amplifier:

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          +Vcc
           |
           Rf
           |
Input ----/\/\---- Output
           |    |
           |    |
          Rin  -Vcc
           |
          GND


The gain of the inverting amplifier (Av) can be calculated using the following formula:

Av = - Rf / Rin

The negative sign in the gain equation represents the inversion of the input signal. The magnitude of the gain is determined by the ratio of the feedback resistor (Rf) to the input resistor (Rin).

In practice, it's essential to choose appropriate resistor values to achieve the desired amplification level and ensure the op-amp remains within its linear operating region. Additionally, feedback capacitors or other compensation components might be added to improve stability and reduce noise.