An inverting amplifier is a type of operational amplifier (op-amp) circuit that amplifies an input signal while inverting its polarity. It uses a negative feedback configuration, where a portion of the output is fed back to the inverting input terminal of the op-amp. This feedback creates a stabilized and controllable gain for the circuit.
The basic schematic of an inverting amplifier is as follows:
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V_in
|
R1
|
+----|----+
| | |
| R2 Rf
| | |
+----|----+
|
V_out
Here's how the circuit works:
An input signal, V_in, is applied to the inverting input terminal of the op-amp through resistor R1.
The non-inverting input terminal of the op-amp is typically connected to the ground (0V).
Resistor R2 connects the inverting input terminal to the output, V_out, providing negative feedback.
Resistor Rf (feedback resistor) connects the output to the inverting input, completing the feedback loop.
The gain of the inverting amplifier can be calculated using the following formula:
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Gain (A) = -Rf / R1
Where:
Rf is the value of the feedback resistor (resistor connected between output and inverting input).
R1 is the value of the input resistor (resistor connected between inverting input and input signal).
The gain, denoted by "A," is negative in an inverting amplifier, indicating that the output signal will be an inverted and amplified version of the input signal. The magnitude of the gain is determined by the ratio of the feedback resistor to the input resistor. By choosing appropriate resistor values, you can set the desired amplification level of the input signal.