An inverting amplifier is a basic electronic circuit configuration commonly used in analog signal processing. It's a type of operational amplifier (op-amp) circuit that takes an input voltage and produces an output voltage that is the inverse (opposite in sign) of the input voltage. This circuit is widely used in various applications, including signal amplification, waveform generation, and more.
Here's how the inverting amplifier circuit works:
Components:
Operational Amplifier (Op-Amp): A high-gain differential amplifier that has two input terminals (inverting and non-inverting) and one output terminal.
Feedback Resistor (Rf): This resistor is connected between the output of the op-amp and the inverting input terminal.
Input Resistor (Rin): This resistor is connected between the inverting input terminal of the op-amp and the input signal source.
Ground (GND): Common reference point for the circuit.
Circuit Configuration:
The inverting amplifier circuit configuration involves connecting the inverting input terminal of the op-amp to the input signal source via the input resistor (Rin). The non-inverting input terminal is usually connected to ground. The output of the op-amp is connected back to its inverting input terminal through the feedback resistor (Rf).
Operation:
When an input voltage (Vin) is applied to the inverting amplifier circuit, a few things happen:
The op-amp tries to keep its two input terminals at the same voltage (virtual short assumption for ideal op-amps), meaning it will strive to make the voltage at the inverting input equal to the voltage at the non-inverting input (which is usually grounded).
The current flowing through Rin causes a voltage drop across it. This voltage drop at the inverting input creates a corresponding voltage at the output through the feedback resistor (Rf).
Since the op-amp's gain is very high, it effectively forces the output voltage to change in a way that reduces the voltage difference between the inverting and non-inverting inputs.
Output Voltage Calculation:
The relationship between the input and output voltages can be expressed using the following equation:
Vout = - (Rf / Rin) * Vin
This equation shows that the output voltage (Vout) is the negative of the input voltage (Vin) multiplied by the ratio of the feedback resistor (Rf) to the input resistor (Rin).
Amplification and Phase Inversion:
The inverting amplifier provides signal amplification, and it inverts the input signal's phase by 180 degrees. The amplification factor is determined by the ratio of the feedback resistor (Rf) to the input resistor (Rin). Larger values of Rf relative to Rin result in greater amplification.
Remember that real-world op-amps may have limitations, such as bandwidth, slew rate, and input/output voltage ranges, which could affect the accuracy of the ideal behavior described above. However, the basic principle of an inverting amplifier remains the same.