A circuit board assembly includes: a circuit board having opposite first and second surfaces and formed with a first through-hole defined by a hole-defining wall that extends between and that terminates at the first and second surfaces and that cooperates with the first and second surfaces to define first and second turns, respectively, the circuit board further having an abutting wall that extends between and that terminates at the first and second surfaces and that cooperates with the second surface to define a third turn; and an electric wire having a fixed end that is soldered to the circuit board, extending through the first through-hole, and passing over the first, second and third turns of the circuit board so as to form an inflection region between the first and second turns.