Ultrasounds Physics and Production

Vocabulary flashcards covering the definition, piezoelectric production, and structural components used in generating ultrasounds.

Ultrasounds

A longitudinal soundwave with a frequency above the audible range of $20\,Hz$ to $20,000\,Hz$, specifically having a frequency $> 20\,kHz$.

Piezo electric effect

The phenomenon where a crystal, such as quartz, changes shape by expanding or contracting depending on the direction of an applied electric field.

Quartz

A material used to produce ultrasounds, made of repeating tetrahedral silicate units where oxygen ions are not rigidly fixed and can move in an electric field.

Production of ultrasounds (Method)

Applying an AC voltage across a crystal to make it vibrate at the frequency of the applied voltage, specifically utilizing resonance by matching the AC frequency to the crystal's natural frequency.

Forced oscillation

The simple harmonic motion (SHM) of a crystal vibrating at the specific frequency of an applied AC voltage.

Resonance (in ultrasound production)

Occurs when the frequency of the applied AC voltage matches the natural frequency of the crystal, causing the crystal to produce ultrasounds.

Oxygen ions

Negatively charged particles within quartz that experience an electric force in an electric field, causing the crystal to change shape.

Ultrasound transducer components

Basic structure including a quartz crystal, silver plates, backing material, casing, coaxial cable, and an acoustic material/window.