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Background Information

Operational amplifiers are widely used in audio equipment. For example, audio mixers allow individual audio channels to be amplified or attenuated in order to adjust the overall sound. One common operational-amplifier configuration used for signal processing is the inverting amplifier. By selecting appropriate resistor values, the amplification factor can be adjusted to achieve the desired signal level. In an inverting amplifier, the gain is determined by the ratio of the feedback resistor to the input resistor.

• The input voltage Ue is at the inverting input of the operational amplifier.
• The feedback is done by a voltage divider of R1 and R2.
• The voltage gain is \(A_{\mathrm{V}} = -\frac{R_2}{R_1}\)