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In 1906 , Lee De Forest found that a small voltage on a grid of metal wires between the cathode and anode could control a much larger current in a beam of cathode rays passing through a vacuum tube .
 Lee De Forest
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Lee De Forest