 In his method patented in 1925, Grabovsky proposed a new principle of the TV imaging based on the vertical and horizontal electron beam sweeping under high voltage that is widely used in the modern cathode-ray tubes.A historian and ethnographer Boris Golender (Борис Голендер in Russian) in his video lecture described in details where and how the inventor Boris Grabovsky demonstrated a first fully electronic TV set to committee and public in summer 1928.Although this date of demonstration of the fully electronic TV set is the earliest known so far, most of the modern historians claim that either Vladimir Zworykin  or Philo Farnsworth  were supposedly first.