A transducer with more than one active element is called:

• A. Multipurpose
• B. Annular
• C. Mechanical
• D. Array

Answer: (D)

Having more than one active element defines an array transducer. With multiple elements, each can be excited with a specific timing, or phasing, to shape and steer the ultrasound beam electronically. This beamforming capability lets you focus at different depths and steer the beam without physically moving the transducer, which improves lateral resolution and enables dynamic focusing as you image at various depths.

An annular transducer is a multi-element design using concentric rings, and while it employs several elements, the general term for a device with multiple active elements is array. A mechanical transducer uses a single element that is moved to scan, and multipurpose isn’t a standard term for a transducer type.