Frequency dependence of amplification

Discussion in 'Homework Help' started by boks, Dec 19, 2008.

  1. boks

    Thread Starter Active Member

    Oct 10, 2008
    How is the frequency dependence of amplification influenced by feedback?
  2. mik3

    Senior Member

    Feb 4, 2008
    If the feedback is negative the bandwidth of the amplifier increases. Whereas, if the feedback is positive the bandwidth decreases.
  3. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
    Negative feedback broadens the frequency response.....actually, it DECREASES the gain to the level it would be at the high frequency cutoff frequency. The high frequency cutoff freq is what it is. You can't make that any bigger, but you can make everything else smaller to match it.

    There is one small addendum to this....called feed-forward compensation, where you actually increase the transient response at the high end. This is used by putting a VERY small (sometimes called a "gimmick") capacitor between the non inverting input and the output. This has to be done with great discretion, though.