question: At what time did Bardeen and Brattain experiment on increasing signal output ?
answer: November 17 , 1947 to December 23 , 1947
turker_answer: Bardeen and Brattain experimented on increasing signal output from November 17 , 1947 to December 23 , 1947 .
rule-based: Bardeen and Brattain experiment on increasing signal output at November 17 , 1947 to December 23 , 1947 .