Magnetic Buzzer with Circuit Built in -7VDC, 12mm buzzer -Internal oscillator buzzer -Buzzer alarm Magnetic Buzzer with Circuit Built in (Active circuit)(Diameter 12mm by Height 9.5mm, 2700Hz, 3~15VDC)1, No minimum ... digital cameras, electronic dictionaries, ultrasonic planimeters, medical devices, micro-displacement positioner, high voltage generator, facsimile machines, telephones, electronic ...