An inverting amplifier is a type of operational amplifier (op-amp) circuit configuration that produces an inverted output voltage relative to its input voltage. It's commonly used to amplify and invert the input signal, resulting in an amplified output signal with a reversed polarity. The basic inverting amplifier circuit consists of an op-amp, two resistors (R1 and R2), and a feedback loop. The input signal is applied to the inverting input terminal (-) of the op-amp, and the output is taken from the output terminal.
Here's how the inverting amplifier circuit works:
Input Signal (Vin): The input signal (usually a voltage) is applied to the inverting input terminal (-) of the op-amp.
Resistors (R1 and R2): The two resistors, R1 and R2, form a voltage divider network. R1 is connected between the input terminal and the inverting input of the op-amp, while R2 is connected between the inverting input and the output terminal.
Feedback Loop: The output voltage of the op-amp (Vout) is fed back to the inverting input through the resistor R2. This feedback mechanism helps control the gain of the amplifier and stabilize its behavior.
Amplification and Inversion: The output voltage of the inverting amplifier (Vout) is calculated using the following formula:
Vout = - (R2 / R1) * Vin
As you can see, the output voltage is the negative of the input voltage multiplied by the ratio of R2 to R1. This results in both amplification and inversion of the input signal.
Characteristics of an inverting amplifier:
Gain: The gain of the inverting amplifier is determined by the ratio of the resistors R2 and R1. Higher values of R2 relative to R1 result in higher gain.
Inversion: The most distinctive feature of the inverting amplifier is that it produces an inverted output signal relative to the input signal's polarity. If the input voltage increases, the output voltage decreases, and vice versa.
Stability: The feedback loop in the circuit helps stabilize the amplifier's performance by reducing the influence of noise and fluctuations.
Frequency Response: The frequency response of the inverting amplifier is determined by the bandwidth of the op-amp and the values of the resistors used in the circuit.
Common Uses: Inverting amplifiers are commonly used in various applications, such as signal conditioning, audio amplification, and instrumentation, where an inverted and amplified version of the input signal is required.
In summary, an inverting amplifier circuit uses an op-amp and a feedback network of resistors to produce an amplified and inverted output signal relative to the input signal's polarity. It's a fundamental building block in electronics for signal processing and amplification tasks.