How Does a Missing Component in the Feedback Loop Affect the Transfer Function?

AI Thread Summary
The discussion centers on the confusion regarding the absence of a component (H1) in a feedback loop and its impact on the transfer function. Without H1, the transfer function simplifies to C/R = Gcs x Gps, as the feedback term is absent. Participants clarify that Gcs and Gps should not be placed in the denominator since they are part of the forward path. The conversation also includes light-hearted remarks about forgetting control theory concepts. Ultimately, the importance of understanding feedback loops in control systems is emphasized.
Femme_physics
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I'm confused by the fact there's nothing in the feedback loop here

http://img706.imageshack.us/img706/6075/feedbackloop.jpg


For instance, if I had "H1" in the feedback loop I'd do

C/R = (Gcs x Gps) / (1+H1)

But since I don't have H1... is it simply

C/R = (Gcs x Gps) / 1 = Gcs x Gps

?
 
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You have 1 loop.
And yes, you don't have H1 in the returning part of the loop, so you can simply leave that out.
But you still have Gcs and Gps in the forward part of the loop.
Shouldn't you put those in the denominator?
 
I seem to have completely forgot control theory. Allow me to slap myself twice in the face silly and strap myself to the chair with old materials.

Sorry to have bothered you for trifles, sensei :)
 
Femme_physics said:
I seem to have completely forgot control theory. Allow me to slap myself twice in the face silly and strap myself to the chair with old materials.

Sorry to have bothered you for trifles, sensei :)

Trifles are better than nothing. ;)

Can I slap you a couple of times too as long as you are strapped to a chair anyway?
 
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