An inverting amplifier is a basic operational amplifier (Op-Amp) configuration that produces an output that is the opposite (inverted) in polarity to its input signal. In other words, if the input voltage increases, the output voltage decreases, and vice versa. It is commonly used in various electronic applications, such as signal processing and audio amplification.
The schematic symbol for an operational amplifier looks like this:
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+------+
Input | |
----->| Op-Amp |-----> Output
| |
+------+
Here's the basic circuit diagram of an inverting amplifier using an operational amplifier:
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+Vcc
|
Rf
|
Input--|---[Op-Amp]--- Output
|
Rg
|
-Vcc
Where:
Vcc and -Vcc represent the positive and negative power supply voltages, respectively.
Rf is the feedback resistor (connected between the output and the inverting input of the Op-Amp).
Rg is the input resistor (connected between the inverting input and the input signal source).
The voltage gain (A_v) of the inverting amplifier can be calculated using the following formula:
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A_v = - Rf / Rg
The negative sign in the gain equation indicates the inversion of the output with respect to the input signal. The voltage gain value is typically expressed in decibels (dB), and it represents the ratio of the output voltage to the input voltage. The larger the value of the gain, the greater the amplification provided by the circuit.
Keep in mind that the actual performance of the inverting amplifier will also depend on the characteristics of the operational amplifier used and the choice of appropriate resistor values. Additionally, practical considerations, such as input and output impedance, bandwidth, and noise, need to be taken into account when designing and implementing an inverting amplifier circuit.