I am reading Two cavity Klystrons but not able to understand at all. I have a lot of questions about its working. Q1. Firstly, as we know that Klystrons are used as amplifiers for microwave frequency and conventional vaccum tubes can't be used due to interelectrode capacitance and lead inductance effect,but though microwave signals can be amplified by Klystrons is there any limitation to the Amplitude of the input signal to the Buncher Cavity? Q2.An electron beam is generated due to DC voltage and this beam gets velocity modulated in buncher cavity due to which bunching takes place and energy is supplied to electron in buncher cavity by the input Microwave signal in terms of velocity(i hope so as kinetic energy) and this energy is lost in catcher cavity , but why is it lost there ? I mean how and why does it happens?