An inverting amplifier is a type of electronic circuit configuration used to amplify an input signal while inverting its polarity, which means the output signal is mirrored or flipped compared to the input signal's waveform. This type of amplifier is commonly used in various applications, such as signal processing, audio amplification, and instrumentation.
The basic building blocks of an inverting amplifier circuit include an operational amplifier (op-amp) and a few passive components like resistors. An op-amp is a high-gain voltage amplifier with two input terminals (inverting and non-inverting) and one output terminal. In an inverting amplifier, the inverting input terminal (-) is connected to the input signal source, and the non-inverting input terminal (+) is typically grounded or connected to a reference voltage.
Here's how an inverting amplifier circuit works:
Input Signal: The input signal (usually a voltage) is applied to the inverting input terminal of the op-amp.
Feedback Network: The feedback network consists of a resistor (Rf) connected between the op-amp's output and inverting input terminal. Another resistor (R1) is connected from the inverting input terminal to a reference point (often ground or a specific voltage level).
Amplification and Inversion: When the input signal is applied to the inverting terminal, the op-amp amplifies the voltage difference between its two input terminals. The feedback network determines the gain of the amplifier. The output voltage (Vout) is proportional to the difference between the voltages at the inverting and non-inverting terminals, which causes the polarity inversion.
Operational Principle: The op-amp tries to maintain the voltage at its inverting and non-inverting inputs at the same level (virtual short). Due to the configuration of the feedback resistors, the op-amp adjusts its output voltage to create a voltage at the inverting input that satisfies this requirement. This leads to the inverted output signal.
The gain (A) of the inverting amplifier is determined by the ratio of the feedback resistor (Rf) to the input resistor (R1):
=
−
1
A=−
R
1
R
f
The negative sign indicates the inversion of the signal. By choosing appropriate resistor values, the amplification factor can be adjusted. Higher values of Rf in relation to R1 result in higher amplification.
In summary, an inverting amplifier circuit is a useful tool in electronics for amplifying and inverting input signals. It offers design flexibility and finds applications in various domains where signal inversion and amplification are required.