Here is a formula you can try that extracts text AFTER the word "circuit" and before the comma that follows after said word.
=TRIM(LEFT(SUBSTITUTE(MID(SUBSTITUTE(LOWER(A1),"circuit",REPT(" ",LEN(A1))),LEN(A1)+1,LEN(A1)),",",REPT(" ",LEN(A1))),LEN(A1)))
EDIT: Curse those case sensitivities!