. When a voltage pulse (Vpulse) is applied across the poles of the PZT material, the
mechanical vibration is stretched over time as it slowly decreases in magnitude; a behavior similar to the ringingeffect of a metal bell when stroked. For most applications, the ringing-effect is an undesirable outcome since the
reflected ultrasound can arrive before the ringing is adequately damped if the material is thin. Therefore, techniques
such as dampening-material, or backing-material, is applied to the back side of the PZT disc to greatly reduce the
number of resonant cycles produced. The backing-material, however, also dampens the signal amplitude of the
generated ultrasound wave, which is an undesired outcome. With adequate dampening, or smaller numbers of cycles
produced, we can achieve higher measurement resolution in order to test thinner material, or distinguish finer details