A new design of capacitance transducer for ultrasonic displacement detection

A design is presented for a capacitance transducer for use at metal surfaces. Provision is made for alignment of the electrode relative to the sample. An advantage over previous designs is the device's resistance to damage following arcing or accidental contact of the electrode to the metal surface. The device has been tested by use of standard acoustic sources, and found to perform satisfactorily over the required bandwidth.