# How to calculate the output impedance of amp with feedback

1. ## calculate output impedance

How to calculate the output impedance of amp with feedback when I want to calculate the openloop gain,thank you. •

2. ## how to calculate rc impedance

210k resistance is your load? •

3. ## how to calculate output impedance op amp

To Calculate:
Let Ro = Open Loop Op Amp output impedance
. Ao = Open loop op amp gain
. Ac = Closed loop op amp gain
. Rc = Closed loop op amp output impedance
. Then:
Rc = Ro(Ac/Ao)

To measure, using the circuit that you propose;
Let Vs = the "battery" voltage
. Rc = Closed loop op amp output impedance
. Rl = the load resistor (the 210K resistor that you show)
1) Remove the load and battery
2) Tweek the input so that the output voltage = exactly 0
3) Re-apply the load, Vs
4) Adjust the load (Rl) so that the output current is just below the
. op amp rated load current for linear operation.
Let Vo = the output voltage under these conditions.
. Then:
Rc = VoRl / (Vs - Vo)
.
The problem with this method is that Vo is very small, making accurate measurements difficult.
.
Regards,
Jon •

4. ## caluclate output impedance operational amplifiers

I think not only taking account of RL but also the resistance in the feedback net, right? --[[ ]]--