An inverting amplifier is a fundamental electronic circuit commonly used in analog signal processing and amplification. It is a type of operational amplifier (op-amp) configuration that produces an inverted output signal compared to the input signal. In other words, when the input voltage increases, the output voltage decreases, and vice versa.
The basic setup of an inverting amplifier consists of an operational amplifier and two resistors, one connected to the inverting input terminal (-) of the op-amp and the other connected between the output and the inverting input terminal. The non-inverting input terminal (+) of the op-amp is usually connected to the ground (0V).
Here's a simplified schematic of the inverting amplifier circuit:
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+Vcc
|
Rf
|
Vin --|--->|--- Vout
|
Rg
|
GND
Vin: The input voltage applied to the inverting input terminal of the op-amp.
Vout: The output voltage produced by the inverting amplifier.
Rf: The feedback resistor connected between the output and the inverting input terminal of the op-amp.
Rg: The input resistor connected between the inverting input terminal and the input voltage source.
The gain of the inverting amplifier is determined by the ratio of the feedback resistor (Rf) to the input resistor (Rg). The voltage gain (Av) of the inverting amplifier can be calculated using the following formula:
Av = -(Rf / Rg)
The negative sign in the formula signifies the inversion of the output with respect to the input. This means that if the input voltage increases, the op-amp's output will decrease by the calculated gain, and if the input voltage decreases, the output will increase by the same gain.
The inverting amplifier is a versatile circuit used in many applications, such as audio amplification, signal conditioning, active filters, and instrumentation circuits. It offers high input impedance, low output impedance, and can provide both voltage amplification and inversion of signals, making it a crucial building block in various electronic systems.