Ключевые слова: amplifying vacuum tube, anode, background, cathode, connecting pin, control grid, development, device, electric current, electric field, electrode, electron tube, electronic device, electronic function, electronics, evolution, getter, glass envelope, industry, old, old things, oldfashioned, pentode, potential difference, power amplification, powerful, progress, retro, signal amplification, switching, technology, terminal, thermionic emission, triode, tube, vacuum, vacuum tube, valve, vintage, white,