🔍 Key Concepts

• How the resonant cavity of a klystron determines its basic frequency • The difference between mechanical tuning (changing cavity dimensions) and electronic tuning (changing electrode voltages) • Role of the repeller (reflector) voltage in a reflex klystron’s frequency control

💭 Think About

• Which part of the klystron actually sets the main (central) frequency: the cavity, the grids, or the power supply? • Think about which control would reasonably give you only a small, fine-tuning range versus which one could shift the operating frequency over a wider range. • Among the listed voltages (anode vs. repeller) and structures (cavity, buncher grids), which ones are physically involved in forming the resonant circuit?

✅ Before You Answer

• Identify which option, if any, mentions changing the physical resonant cavity for larger frequency shifts. • Check which electrode’s voltage is commonly used for fine (small) frequency adjustments in a klystron. • Eliminate any choice that claims large frequency changes can be made simply by adjusting an operating frequency or a voltage that is not directly part of the resonant structure.