Measuring the frequency response of an optocoupler (e.g. PC817C) with different pull-up resistors using a Bode 100.

[AlouetteRAISER]

My test reference circuit is from Mr. Christophe Basso's book: "Designing Control Loops for Linear and Switching Power Supplies By A Tutorial Guide"

The picture is showed as follow.

Unfortunately, it may be a problem with my test circuit, or maybe the Bode 100's are not set up yet and I'm not getting results.

[AlouetteRAISER]

Please forgive me if there are any grammatical errors in my English. I am not very good at English.