positive feed back in opamp

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sayurabh

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if i give positive feedback in opamp how does value of gain changes of both non-invering and inverting amplifier i am confused all buks have worked on negative feed back but what happens if we give positive feedback and removing the negative feedback from opamp
 

Positive feedback in Inverting/Non-inverting config. (this is, if you connect the feedback resistor from output to the positive input terminal) causes saturation. Thus, the output saturates.

Why don't you try analyzing it yourself, using the same techniques as those for -ve f/b?
 

Positive feedback converts amplifier into Schmitt trigger (i.e. comparator with hysteresis).
 

hysteresis is import
 

In positive feedback the gain is ideally infinte...In real time opamp the open loop gain is so large that the output of the opamp saturates to either +Vcc or -Vcc...
 

positive feedback increases the gain of any circuit.... since the gain of the opamp is already very high and hence positive feedback results in opamp output saturating unless your input is very small....
 

it becomes a schmitt trigger.
 

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