When a ferromagnetic rod is placed along a magnetic field it undergoes a small change in it length. If the steady magnetic field is replaced by an alternating magnetic field it undergoes alternate extension and contraction. If the frequency of the alternating magnetic field is high the rod starts vibrating exhibiting longitudinal vibrations. When the frequency of the applied field is high the rod produces ultrasonic waves in the surrounding medium.

APPLICATION:

Acoustic transducer : SONAR, Hydrophone, ultrasonic cleamimg, ultrasonic friction welding.

Actuator: pump, Active valve, Rotary motor.

Sensor: vibration sensor, position sensor, torque sensor.