How do we relate the various quantities we talked about in the previous article? Fig. 1 above relates the quantities on a gain vs. frequency plot – sometimes called a Bode plot.
The graph shows an example of what a typical plot would look like for any given voltage op-amp. As you note, the maximum gain vs. frequency for the op-amp intrinsic gain is a strong function of frequency, usually falling off at a rate of 20DB per decade with increase in frequency, starting at approximately 10 to 100 HZ. We can extend the bandwidth of our op-amp circuit by actually attenuating the maximum amplifier intrinsic gain using the beta factor to multiply it by a number less than 1. For example if we reduced the gain by the factor beta (A *beta or 60DB reduction), we achieve the target gain of 20DB out to approximately 5KHZ. So larger values of beta reduce gain but increase the flat bandwidth.
The graph shows an example of what a typical plot would look like for any given voltage op-amp. As you note, the maximum gain vs. frequency for the op-amp intrinsic gain is a strong function of frequency, usually falling off at a rate of 20DB per decade with increase in frequency, starting at approximately 10 to 100 HZ. We can extend the bandwidth of our op-amp circuit by actually attenuating the maximum amplifier intrinsic gain using the beta factor to multiply it by a number less than 1. For example if we reduced the gain by the factor beta (A *beta or 60DB reduction), we achieve the target gain of 20DB out to approximately 5KHZ. So larger values of beta reduce gain but increase the flat bandwidth.
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