TC 9-62
Figure 7-17. Closed-loop Frequency-response Curve for Gain of 100
7-78. In Figure 7-18, more feedback has been used to decrease the gain of the circuit to
10. Now the bandwidth of the circuit is extended to about 100 KHz.
Figure 7-18. Closed-loop Frequency-response Curve for Gain of 10
7-79. The relationship between circuit gain and bandwidth in an operational-amplifier
circuit can be expressed by the GAIN-BANDWIDTH PRODUCT (GAIN x
BANDWIDTH = UNITY GAIN POINT). In other words, for operational-amplifier
circuits, the gain times the bandwidth for one configuration of an operational amplifier will
equal the gain times the bandwidth for any other configuration of the same operational
amplifier. In other words, when the gain of an operational-amplifier circuit is changed (by
changing the value of feedback or input resistors), the bandwidth also changes. But the
gain times the bandwidth of the first configuration will equal the gain times the bandwidth
of the second configuration. The following example should help you to understand this
concept.
7-24
TC 9-62
23 June 2005
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