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Transducer

  • Objective
    • Overall specs
      • At 3.5MHz
      • -3dB at roughly 2 - 5 MHz-
    • Getting a good-resolution signal from a robust transducer, which may or may not include the following specs:
      • Immersible
      • With a focal distance of 75mm (cf the models at Transducer Models)
      • 10mm in diameter (it seems that smaller have smaller focal distance)
      • Materials : possibility to use 1-3 composite
      • with a thin backing - and a low-footprint backing
      • if possible, low-cost !
  • Requirements
    • Getting a « top » to pulse
    • As short as possible
    • As high voltage as possible (within specs)
  • Tests with Emile

Transducer suppliers

Nom Site
Imasonic http://www.imasonic.com/Company/IdentityF.php
PiezoTechnologies http://www.piezotechnologies.com/documents/120710-material-data-sheet.aspx
Smart Materials http://smart-material.com
Blatek http://blatek.com
American Piezo http://americanpiezo.com
STI http://sti-ultrasound.com
Valpey http://www.ctsvalpey.com/
OKOS http://www.okos.com/transducers
Sofranel http://www.sofranel.com/fr
Olympus http://www.olympus.fr/
Sonaxis http://www.sonaxis.com/accueil.html
Ultrasound Transducer http://www.ultrasoundtransducers.com/
PiezoSolutions http://www.piezosolutions.net/
SonicConcepts http://www.sonicconcepts.com/
SonoMecha http://www.sonomecha.com/
Piezo.com http://www.piezo.com/
TRS-Tech http://www.trstechnologies.com/
Ferroperm http://www.ferroperm-piezo.com/

Commercial transducer

We are using a commercial transducer with a center frequency of 5 MHz which has an impedance Z defined by:

  • Re(Z) = 9.29 Ohms
  • Im(Z) = -12.5 Ohms

With our electronic circuit we access to pulse of amplitude given by the VCC (here 20 V):

Raw pulse.png

the rise time is 420 ns. Ideally, we want a pulse with a duration of 100 ns (half the period of the transducer) with an amplitude of -100 V.

When we plug the transducer, the pulse change:

Transducer pulse.png

the amplitude of the pulse is now -12.8 V and the rise time is 5.4 us. The impedance of the transducer reduce the amplitude of the pulse and increase the rise time. By knowing the equivalent electronic circuit we could design the electronic circuit to access the desire pulse.

Smart Materials transducer

Smart Materials has lend us transducers in order to test them. Their central frequency is 5 MHz and they are focalised at 80 mm. Due to the specific (LEMO) connector, it take times for us to test them. It is done now. First if we send a pulse 15 V high, the tension measure at the terminals of the transducer is still 15 V high :

Pulse SM transducer.png

The measured echo from a metal plate as a relatively high amplitude :

Echos SM transducer.png

more than 200 mV peak to peak. It is the highest amplitude we have received on all the transducers we have tested.

Example of recycling transducers

Testing the Red and Yellow transducers

We have been recycling the following S-VRW77AK piezoelements. Color pairs are as follows: Yellow/DeepBlue, and Red/LightBlue.

After reconnecting the cables, the whole setup was installed in a plastic tube and waterproofed.

Media in category "Transducer"

The following 6 files are in this category, out of 6 total.

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