Chapter 9: Transducers
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| show | Any device that converts one form of energy into another
🗑
|
||||
| show | transmission: electrical energy from system is converted into sound
reception: sound pulse is converted into electrical energy
🗑
|
||||
| show | property of certain materials to create voltage when they are mechanically deformed
🗑
|
||||
| show | when materials deform (change shape) when voltage is applied
🗑
|
||||
| show | material capable of converting sound into electricity and vice versa
🗑
|
||||
| What is another name for piezoelectric materials? | show 🗑
|
||||
| show | Natural: quartz, tourmaline
Man-made: lead zirconate titanate (PZT)
🗑
|
||||
| What piezoelectric matterial is commonly used in clinical transducers? | show 🗑
|
||||
| PZT is also known as what? | show 🗑
|
||||
| What are the 7 components of a basic transducer? | show 🗑
|
||||
| What is the case made of and what is its purpose? | show 🗑
|
||||
| What is the electrical shield and what is its function? | show 🗑
|
||||
| show | thin barrier of cork or rubber that isolates internal components of the TD from the case;
prevents case vibrations from inducing an electrical voltage in the PZT
🗑
|
||||
| show | positioned in front of the PZT at the face of the transducer;
has an impedance between that of the skin and the active element to increase percentage of transmission
🗑
|
||||
| What between the matching layer and skin also helps with transmission of the sound beam? | show 🗑
|
||||
| show | bonded to the active element to limit "ringing";
commonly composed of epoxy resin impregnated with tungsten
🗑
|
||||
| show | Advantages: shortens SPL and pulse duration, increased bandwidth with decreased Q factor, increases axial resolution (picture quality)
Disadvantages: decreases sensitivity,
🗑
|
||||
| Greater differences in what result in more reflection at a boundary? | show 🗑
|
||||
| PZT impedance is about how much more than skin impedance? | show 🗑
|
||||
| What impedance is between that of skin and PZT? | show 🗑
|
||||
| The impedance of what is between that of the matching layer and skin? | show 🗑
|
||||
| show | 1/4
🗑
|
||||
| The thickness of the active element (PZT) is what the wavelength of sound in the active element? | show 🗑
|
||||
| show | high degree of sound absorption;
acoustic impedance similar to PZT so sound energy moves away from patient into backing material
🗑
|
||||
| What does it mean when its said that backing material causes decreased sensitivity of the TD? | show 🗑
|
||||
| What is resonant frequency and what are some other names for it? | show 🗑
|
||||
| show | PZT cannot vibrate freely so the pulse becomes short duration "click" instead of a long steady tone
🗑
|
||||
| show | many frequencies above and below the resonant frequency
🗑
|
||||
| show | the range between the highest and lowest frequencies emitted from the TD
🗑
|
||||
| What is the relationship between bandwidth and pulse duration? | show 🗑
|
||||
| show | Imaging TD: short pulse, wide bandwidth
CW probe: no backing: long pulse, narrow bandwidth
🗑
|
||||
| In CW transducers, the sound wave's frequency equals what? | show 🗑
|
||||
| With CW transducers, electrical frequency equals what? | show 🗑
|
||||
| With PW transducers, the frequency produced depends on what? | show 🗑
|
||||
| What are the two characteristics of the PZT that determine the frequency of sound from pulsed wave transducer? | show 🗑
|
||||
| The speed of sound in the PZT means what? | show 🗑
|
||||
| With PW TDs, when sound's speed in PZT is faster, the frequency created is what? | show 🗑
|
||||
| show | directly related
🗑
|
||||
| show | about4 times greater than soft tissue.
the range: 4-6mm/us
🗑
|
||||
| With pulsed wave transducers, thinner PZT crystals create what kind of frequency sound pulse? | show 🗑
|
||||
| With PW transducers, a thinner PZT crystal creates what kind of wavelength? | show 🗑
|
||||
| With PW transducers, the thickness of the PZT crystal is related how to frequency? | show 🗑
|
||||
| show | thickness range: 0.2-1mm
🗑
|
||||
| What is the equation for frequency for pulsed wave transducers? | show 🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
quietone055
Popular Physics sets