What is open loop differential gain?

Thread Starter

Elevon

Joined Jun 7, 2020
16
Simple question - what is open loop differential gain?

What is the difference between open loop gain and open loop differential gain? I cant find a definition for the latter anywhere.
 

Papabravo

Joined Feb 24, 2006
14,244
It is the gain applied to the voltage difference between two input voltages with no feedback from the output to the inputs. A typical open loop differential gain might be 200,000. In a practical circuit you would see the amplifier output at the negative rail if the difference is negative, At the positive rail if the difference is positive. In a very small range from [-60 μV,...,60 μ], assuming ±12 VDC rails, there would be a straight line connecting the negative and positive rails with a slope of 200 mV/μV. That is what an open loop differential gain of 200,000 will get you.
 

LvW

Joined Jun 13, 2013
1,078
Simple question - what is open loop differential gain?
What is the difference between open loop gain and open loop differential gain? I cant find a definition for the latter anywhere.
Both are identical.
We speak about "open-loop gain" only if we have to compare it with "closed-loop gain". And in such a case, we generally have to input ports (one inverting and one non-inverting). Best example: Operational amplifier.
Because of the two input nodes we define the voltage between boith inputs as "differential input" - resulting in "differential gain."
 
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