THREE-ELECTRODE CIRCUIT ELEMENT UTILIZING SEMICONDUCTIVE MATERIALS spectrum district of columbia 1948-09-24 6:52 PM First page of US Patent No. 2,524,035 BIBLIOGRAPHY Bardeen, John, and Walter H. Brattain. Three-electrode Circuit Element Utilizing Semiconductive Materials. U.S. Patent 2,524,035. Filed 17 June 1948, issued 3 Oct. 1950.