Why high gain in opamp ?

Status
Not open for further replies.

coolstuff07

Advanced Member level 4
Joined
Mar 9, 2008
Messages
118
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,298
Activity points
1,949
Hi,

Why high gain in opamp ?

Please answer my question.

Bye
 


Read more details here
**broken link removed**
http://focus.ti.com/lit/an/sboa092a/sboa092a.pdf

http://www.dei.unipd.it/~pel/Elettronica_Analogica/understanding_OPAMP_specs.pdf
**broken link removed**
**broken link removed**
**broken link removed**
 

take the buffer as an example. the gain with feedback is =Ao/(1+AoB).since B=1 we have Af=Ao/(1+Ao), now if Ao -->inf Af-->1 ,hence we require high gain in opamp to reduce the dependence of closed loop gain on the open loop gain.The gain of an ideal opamp must depend only on its feedback elements,that's achieved only through a high gain.
 

Hi,

Is it some thing related to virtual ground.

Bye
 

in order to get high open loop gain in a opamp negative feedback system.

b/r
 

first, it depends on the application and not always high gain is desirable. In LNAs, we concentrate on the noise first.

An amplifier is supposed to amplify, the higher the gain, the more the amplification
 

The higher the gain , the opam is more close to ideal model.
 

If one input of your amplifier is connected to virture ground, then, the higher the gain, the other input is closer to virture ground.
 

op-amp is a device which could work both on dc as well as ac.its because it draws no currrent as well as its characteristics like virtual ground,high internal impedance and low output impedance.that it offers such a large gain to voltages specified by its Vcc.
 

sometimes the high gain comes from the request of linearity
 

You'd better learn something about feedback theory to full understand it!
 

Status
Not open for further replies.

Similar threads

Cookies are required to use this site. You must accept them to continue using the site. Learn more…