An inverting amplifier is a type of operational amplifier (op-amp) configuration commonly used in electronic circuits to amplify an input signal while inverting its polarity. It's a fundamental building block in analog electronics. The key characteristic of an inverting amplifier is that the output signal is an inverted and amplified version of the input signal.
The basic setup of an inverting amplifier involves an operational amplifier connected in a specific way:
The inverting input terminal of the op-amp (-) is connected to the input signal source.
The non-inverting input terminal of the op-amp (+) is usually grounded.
The output terminal of the op-amp is connected through a feedback resistor (Rf) to its inverting input terminal (-).
The input signal source is connected through an input resistor (Rin) to the inverting input terminal (-).
The voltage gain (A_v) of the inverting amplifier is calculated using the following formula:
=
−
A
v
=−
R
in
R
f
Where:
R
f
is the feedback resistor (connected between the output and inverting input).
R
in
is the input resistor (connected between the inverting input and the input signal source).
The negative sign in the formula indicates that the output signal is inverted compared to the input signal. The magnitude of the gain is determined by the ratio of the feedback resistor to the input resistor. This configuration allows precise control over the gain of the amplifier by adjusting the values of
R
f
and
R
in
.
Keep in mind that while this formula provides the ideal voltage gain, real-world op-amp circuits might have limitations due to factors such as op-amp open-loop gain, bandwidth, and input/output impedance. Additionally, other considerations like power supply voltage and saturation limits should be taken into account when designing practical amplifier circuits.