An inverting amplifier is a type of operational amplifier (op-amp) circuit configuration that produces an output voltage that is the inverse (or negative) of the input voltage. In other words, when the input voltage increases, the output voltage decreases, and vice versa. This circuit is commonly used in electronics for various applications, such as signal amplification, waveform inversion, and voltage scaling.
The basic schematic diagram of an inverting amplifier circuit is as follows:
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R2
Vin ----|---|---- Vout
| |
R1 |
|
GND
Here's how the circuit works:
The input voltage (Vin) is connected to the inverting input (-) of the operational amplifier.
A feedback resistor (R2) is connected between the output of the operational amplifier and its inverting input (-).
Another resistor (R1) is connected between the inverting input (-) of the op-amp and the ground (GND).
The gain (A) of the inverting amplifier is determined by the ratio of the feedback resistor (R2) to the input resistor (R1). Mathematically, the gain is calculated using the following formula:
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A = - R2 / R1
The negative sign indicates the inverting nature of the amplifier, meaning the output is the inverse of the input.
Let's say you have R1 = 10 kΩ and R2 = 20 kΩ. Using the gain formula, the gain of the inverting amplifier would be:
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A = - R2 / R1
= - (20,000 Ω) / (10,000 Ω)
= -2
In this case, the gain of the inverting amplifier is -2, which means that if you apply an input voltage of, say, 1 volt, the output voltage will be -2 volts. The gain determines the amount of amplification or attenuation that the circuit provides to the input signal.
It's important to note that ideal op-amps have extremely high input impedance and low output impedance, and they can provide high gain with accurate inversion. In practice, there might be limitations due to the op-amp's characteristics and external factors such as power supply constraints.