So is the equivalent load resistance really a "dc" quantity while output impedance is
an "ac" quantity?

Basically, yes.

 

Basically, yes.

Thanks.

 

Thanks. So is the equivalent load resistance really a "dc" quantity while output impedance is
an "ac" quantity? It makes sense that impedance is a dynamic quantity as it changes with the
output current and voltage.

No wrong, all Zin and Zout are the "AC" quantities.
https://forum.allaboutcircuits.com/threads/dynamic-resistance-of-zener-diodes.128697/#post-1053492

 

No wrong, all Zin and Zout are the "AC" quantities.
https://forum.allaboutcircuits.com/threads/dynamic-resistance-of-zener-diodes.128697/#post-1053492

What is "wrong" in the TS's statement?
Yes, Zin is an AC quality but that was not mentioned, only equivalent load resistance and output impedance.
And load resistance is a DC quality.

 

What is "wrong" in the TS's statement?
Yes, Zin is an AC quality but that was not mentioned, only equivalent load resistance and output impedance.
And load resistance is a DC quality.

Maybe I wrongly understood the TS words. But when I look at his LTspice and the way he wants to find the Zin and Zout values.

.meas Zin find v(vin)/i(vs) at 1Khz
.meas Zout(No_Load) find v(Vout)/i(RE) at 1Khz
.meas Zout(With_Load) find v(Vout)/ie(Q2) at 1Khz

It seems that TS dos not understand what Zout is. And how to measure it correctly.