An inverting amplifier is a type of operational amplifier (op-amp) circuit configuration commonly used in electronics to amplify signals. It's called "inverting" because the output signal is phase-inverted with respect to the input signal. This means that if the input voltage increases, the output voltage decreases, and vice versa. The inverting amplifier circuit is widely used due to its simplicity and versatility.
Here's how the operation of an inverting amplifier circuit works:
Components: The basic components of an inverting amplifier circuit include an operational amplifier (op-amp), two resistors (R1 and R2), and a power supply.
Op-Amp Properties: Op-amps are high-gain voltage amplifiers with two inputs (inverting and non-inverting) and one output. In an inverting amplifier, the input signal is connected to the inverting (-) input terminal of the op-amp.
Feedback Network: The resistor network (R1 and R2) connected to the op-amp's inverting input terminal creates a feedback mechanism. The output of the op-amp is connected back to the inverting input through the feedback network.
Operational Principle: The inverting amplifier exploits the fact that the op-amp tries to keep the voltage difference between its two inputs (inverting and non-inverting) at zero. Due to this property, the inverting input attempts to keep the same voltage as the non-inverting input.
Negative Feedback: As the input voltage (Vin) is applied to the inverting input, the op-amp adjusts its output voltage (Vout) in such a way that the voltage at the inverting input matches the voltage at the non-inverting input. This creates a negative feedback loop.
Voltage Division: The voltage divider formed by resistors R1 and R2 plays a crucial role. As the input voltage is applied across R1, a portion of this voltage is dropped across R1 and appears at the inverting input. The rest of the voltage is applied across R2, resulting in a proportional output voltage.
Gain Calculation: The gain (A) of the inverting amplifier is determined by the ratio of the resistance values: A = -R2 / R1. The negative sign indicates the phase inversion of the output.
Output Voltage: The output voltage (Vout) is calculated using the gain formula: Vout = -Vin * (R2 / R1).
Sensitivity: The gain can be adjusted by changing the resistor values. Larger values of R2 relative to R1 result in higher amplification, while smaller values reduce the gain.
Limits: Practical limitations, such as the op-amp's supply voltage and its saturation behavior, can impact the achievable gain and the range of input voltages.
Overall, the inverting amplifier is a versatile building block in electronics, commonly used for signal amplification, signal inversion, and other applications where precise control over gain is required.