Patent ID: 6259245
Filing Date: 2001-07-10
Classification: G01R

Abstract:
An electric-current sensing device comprising:an input ultrasonic transducer assembly consisting ofan input piezoelectric vibrator having two end surfaces perpendicular to the thickness direction thereof,a driving electrode formed on one end surface of said input piezoelectric vibrator,an input ground electrode formed on the other end surface of said input piezoelectric vibrator, andan input vibrating plate cemented to said input piezoelectric vibrator through said input ground electrode;an output ultrasonic transducer assembly consisting ofan output piezoelectric vibrator having two end surfaces perpendicular to the thickness direction thereof,a detecting electrode formed on one end surface of said output piezoelectric vibrator,an output ground electrode formed on the other end surface of said output piezoelectric vibrator, andan output vibrating plate cemented to said output piezoelectric vibrator through said output ground electrode; andan ultrasonic fiber made of a magneto-strictive delay line and connected between said input vibrating plate and said output vibrating plate,said driving electrode and said input ground electrode receiving an input electric signal and causing said input piezoelectric vibrator to vibrate acoustically,said input piezoelectric vibrator transmitting an acoustic vibration therein to said output piezoelectric vibrator through said ultrasonic fiber,said detecting electrode and said output ground electrode detecting an acoustic vibration transmitted to said output piezoelectric vibrator as a delayed electric signal, and sensing an electric current around said ultrasonic fiber from said delayed electric signal, which changes in response to an intensity in magnetic field around said ultrasonic fiber.