Voltage follower. - Electronic Circuits Projects Diagrams Free

sl50 · 8th March 2008, 06:47 AM

Hi all,

I have a quick question. We all know how an opamp voltage follower works, but I am wondering since all the close loop feedback is negative to stablize the system, and keeps it from oscillating, but what about a positive feedback voltage follower. Is there any difference between the negative feedback voltage follower and a positive feedback voltage follower, and will the positive feedback voltage follower oscillate or become unstable?

Thanks for the help.

Diver300 · 8th March 2008, 07:17 AM

An op-amp wired with it's non-inverting input to the output will have the output permanently at one extreem or the other.

It then becomes a schmitt trigger. To make a more useful schmitt trigger it is more common to only have some positive feedback, by using two resistors to devide the feedback voltage. That moves the switch points closer together.

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8th March 2008, 06:47 AM	(permalink)
sl50	Voltage follower. Hi all, I have a quick question. We all know how an opamp voltage follower works, but I am wondering since all the close loop feedback is negative to stablize the system, and keeps it from oscillating, but what about a positive feedback voltage follower. Is there any difference between the negative feedback voltage follower and a positive feedback voltage follower, and will the positive feedback voltage follower oscillate or become unstable? Thanks for the help.

8th March 2008, 07:17 AM	(permalink)
Diver300	An op-amp wired with it's non-inverting input to the output will have the output permanently at one extreem or the other. It then becomes a schmitt trigger. To make a more useful schmitt trigger it is more common to only have some positive feedback, by using two resistors to devide the feedback voltage. That moves the switch points closer together.