Newbie question. Is there any difference between opamp in unity gain configuration (buffer) and opamp in non-inverting configuration with gain of 2? Is there output impedance difference etc?
Might be worth double checking that.....Yes, the input impedance is increased by a factor of the closed loop gain
Rin = Rin*Acl
And output impedance is decreased by the same factor:
Rout = Rout/Acl
I assume Close Loop Gain.Hi Veracohr,
What does Acl mean in your earlier post?
Most likely. The issue is with the input / output resistance relationships with respect to that closed loop gain - as quoted by Veracohr in post #4.I assume Close Loop Gain.
Yes that's what I meant.I assume Close Loop Gain.
I see now. Not the closed loop gain, but the loop gain (1+Aβ), where A is the op amp's open loop gain and β is the feedback network factor R1/(R1+R2). Correct? Sorry for giving out misinformation.Most likely. The issue is with the input / output resistance relationships with respect to that closed loop gain - as quoted by Veracohr in post #4.
No need to apologize. Simple mistake. BTW the loop gain is usually taken to be Aβ. Some people include a negative sign which probably pre-supposes negative feedback is being applied.Yes that's what I meant.
I see now. Not the closed loop gain, but the loop gain (1+Aβ), where A is the op amp's open loop gain and β is the feedback network factor R1/(R1+R2). Correct? Sorry for giving out misinformation.
Perhaps not too important in the context of this thread - nevertheless I like to mention that the loop gain is the gain of the COMPLETE loop, that means: including any sign inversion within the loop. Remember that there are circuits with another active inverting element within the loop - and in this case, the loop is closed using the non-invering input node of the main amplifier.No need to apologize. Simple mistake. BTW the loop gain is usually taken to be Aβ. Some people include a negative sign which probably pre-supposes negative feedback is being applied.
by Jake Hertz
by Jake Hertz
by Jake Hertz