Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Negative-feedback amplifier
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
===Gain with feedback=== In the classical approach to feedback, the feedforward represented by the VCVS (that is, ''g''<sub>21</sub> ''v''<sub>1</sub>) is neglected.<ref>If the feedforward is included, its effect is to cause a modification of the open-loop gain, normally so small compared to the open-loop gain itself that it can be dropped. Notice also that the main amplifier block is [[Amplifier#Unilateral or bilateral|unilateral]].</ref> That makes the circuit of Figure 5 resemble the block diagram of Figure 1, and the gain with feedback is then: ::<math> A_\mathrm{FB} = \frac { A_\mathrm{OL} } {1 + { \beta }_\mathrm{FB} A_\mathrm{OL} } </math> :::<math> A_\mathrm{FB} = \frac {A_\mathrm{OL} } {1 + \frac {R_2} {R_2+R_\mathrm{f}} A_\mathrm{OL} } \ , </math> where the feedback factor Ξ²<sub>FB</sub> = βg<sub>12</sub>. Notation Ξ²<sub>FB</sub> is introduced for the feedback factor to distinguish it from the transistor Ξ².
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)