An inverting amplifier is a basic electronic circuit that amplifies an input signal while inverting its polarity. It is commonly used in analog electronics and is built using an operational amplifier (op-amp) along with a few passive components like resistors.
The basic configuration of an inverting amplifier consists of an operational amplifier connected in a way that the input signal is applied to the inverting (-) input terminal of the op-amp, and the output is taken from the output terminal. A feedback resistor (Rf) is connected from the output terminal to the inverting input terminal, and a resistor (Rin) is connected from the inverting input terminal to the input signal source.
The gain (Av) of an inverting amplifier can be calculated using the following formula:
Av = - Rf / Rin
Where:
Av: Amplification factor or gain of the amplifier.
Rf: Feedback resistor.
Rin: Input resistor.
The negative sign in the formula indicates the inversion of the input signal's polarity. The magnitude of the gain is determined by the ratio of the feedback resistor to the input resistor. The larger the feedback resistor compared to the input resistor, the higher the gain of the amplifier.
Keep in mind that in practical implementations, the op-amp may have certain limitations, and there could be additional factors such as the op-amp's input bias current, input offset voltage, and open-loop gain that might influence the actual performance of the amplifier circuit. Additionally, for the circuit to operate in a linear range, the resistor values and the power supply voltage should be chosen appropriately.