A data acquisition channel is fed by a signal which first passes through a clamping circuit as I draw below. Here in the figure Output goes into the data acquisition board after a 8V clamp circuit:
When I opened the clamp box I saw 2 resistors in series both with input and output of the clamp. Why would those 2 resistors needed along with the Zener diode?
What might be problematic if do not have R1? What might be problematic if do not have R2? What might be problematic if do not have both R1 and R2?/Why not only use Zener for clamp?
I could't figure out scenarios when those resistors needed and how to choose in case.