PA uses a multiple-element probe unlike the manual or automatic UT systems, where the output pulse from each element has its own time delay to produce a constructive interference at a specific angle and a specific depth. These time delays can be incremented to sweep the beam over the desired range of angles (e.g., 30 degrees to 70 degrees) (Anderson et al. 2007a; Crawford et al. 2009). PA displays images in real time showing the depth and location of the indications relative to the probe and with the computer software is able to display the ultrasound signal response overlaid on the test piece.
The Probes of the Phased Array is the combination of multiple conventional probes. At one phased array probes various elements (one conventional probe consists of one element usually) can be fixed in an array. Most of the phased array probes have 64, 128 and 256 elements. At one-time desired number of elements can be activated. E.g. only 5 elements can work while others may not work out of 64 or 128. This arrangement helps to focus and steer the angles.