Cathode switch — The first amplifier tube

Presented in this paper is detailed study of the invention of the first amplifying vacuum tubes. It is shown that Robert von Lieben has designed the original vacuum tube amplifier only to increase the low-frequency electrical oscillations (telephone translation), while the three-electrode vacuum tube created by Lee de Forest was created specifically to enhance the radio antenna received radio. It is noted that these inventions have different prototypes: cathode-ray tube — for von Lieben, and oscillation valve — for de Forest. Comparing the dates of the received patents two scientists, it is obvious that priority in the invention of vacuum electronic lamp for electric signal amplification, belongs to Robert von Lieben, and radio frequency amplification belongs to Lee de Forest.