This crossed-field tube uses a heated cathode surrounded by a solid copper anode block with tuned resonant cavities. A strong magnetic field forces emitted electrons into a circular path, where they sweep past the cavities and induce high-frequency microwave oscillations. It remains the core power source in microwave ovens and certain high-power radar transmitters.
Heard on the job
Check the filament voltage on the cavity magnetron before you condemn it for low output power.