Julius Edgar Lilienfeld (April 18, 1882 – August 28, 1963) was an Austro-Hungarian-born German physicist and electronic engineer. He was born to a Jewish family in Lemberg in Austria-Hungary (now called Lviv in Ukraine) and moved to the United States in the early 1920s (he became an American citizen in 1934). Lilienfeld is credited with the first patents on the field-effect transistor (1925) and electrolytic capacitor (1931).