We present an overview of techniques and computer codes developed by us for systematic design of depressed collectors with special reference to devices that use gyrating electron beams. These techniques facilitate achievement of high power levels in electron tubes. ProfilEM is an aid to controlling the trajectories of primary electrons. BSCAT provides for tracing the trajectories of backscattered electrons. Multiple generations of backscatter can be obtained, while keeping the number of rays to be tracked within manageable limits. We describe examples of applying these codes to the case of two‐stage depressed collectors for a 1.5 MW 110 GHz gyrotron. © 2003 American Institute of Physics