-2
\$\begingroup\$

This question already has an answer here:

I was looking at the question "what feedback exactly means"(applied in Op-amps). In the negative feedback even though there is a decrease in the op-amps overall gain, it's widely used because it improves the frequency response of the operational amplifier. So what does this mean exactly?

\$\endgroup\$

marked as duplicate by Voltage Spike, Dmitry Grigoryev, Autistic, Andy aka op-amp Dec 23 '16 at 13:50

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • \$\begingroup\$ I don't think those are duplicates. This question is about how negative feedback influences the frequency response, not how negative feedback works in general. \$\endgroup\$ – Fritz Dec 21 '16 at 18:09
  • \$\begingroup\$ Please provide a link to the question you looked at. \$\endgroup\$ – Andy aka Dec 21 '16 at 18:10
  • \$\begingroup\$ "...even though there is a decrease in the op-amps overall gain...it improves the frequency response..." I believe the answer you're looking for has to do with gain and phase. For stability, the gain of an op-amp must fall below 0dB when the phase reaches -180 degrees, thus deliberately lowering the gain with feedback can ensure a stable response. \$\endgroup\$ – calcium3000 Dec 21 '16 at 18:46
  • \$\begingroup\$ I am just trying to understand what "improved frequency response" means, in simple words! \$\endgroup\$ – C.A Dec 22 '16 at 17:47
0
\$\begingroup\$

Negative feedback decreases the gain at low frequencies but does not affect it much at high frequencies. The frequency range over which the gain is almost constant is increased. Compare the -3dB points of the two amplifier circuits below:

schematic

simulate this circuit – Schematic created using CircuitLab

enter image description here

\$\endgroup\$

Not the answer you're looking for? Browse other questions tagged or ask your own question.