Ultrasonic Transducer Usage Question

[Jim Flanagan]

Hi...
I've come across some surplus 24KHz transducers and wanted to know if it
is possible to use them for either transmitting AND receiving. I tried
some internet searching, but was never able to get a definate answer.
It seems that vendors sell some which are meant for receiving and some
for transmitting. However, I remember, sometime in the past reading
where you COULD use a transducer as both receiver and transmitter.
Your thoughts would be appreciated.

Thanks,
Jim

 

[John Fields]

Hi...
I've come across some surplus 24KHz transducers and wanted to know if it
is possible to use them for either transmitting AND receiving. I tried
some internet searching, but was never able to get a definate answer.
It seems that vendors sell some which are meant for receiving and some
for transmitting. However, I remember, sometime in the past reading
where you COULD use a transducer as both receiver and transmitter.
Your thoughts would be appreciated.

 

[James Meyer]

Hi...
I've come across some surplus 24KHz transducers and wanted to know if it
is possible to use them for either transmitting AND receiving.

99 times out of 100, you use the same transducer for both transmitting
and receiving.

Jim (the other one) Meyer

 

[Winfield Hill]

James Meyer wrote...

99 times out of 100, you use the same transducer for both transmitting
and receiving.

Jim (the other one) Meyer

What're some examples of not being able to use 'em for transmitting?

 

[Mac]

Hi...
I've come across some surplus 24KHz transducers and wanted to know if it
is possible to use them for either transmitting AND receiving. I tried
some internet searching, but was never able to get a definate answer.
It seems that vendors sell some which are meant for receiving and some
for transmitting. However, I remember, sometime in the past reading
where you COULD use a transducer as both receiver and transmitter.
Your thoughts would be appreciated.

Thanks,
Jim

You have very little to lose by buying them and trying them out. Hook one
up to a signal generator at 24 KHz (5 V peak-to-peak) and hook the other
one up to an oscilloscope. Hold them at a separation of 2 or 3 feet,
and set the oscilloscope up to show both the transmit and receive
waveform. Measure the gain (Vtx/Vrx). Then swap them and see if you see
any difference.

These guys are usually very narrow-band, so make sure you are at 24 KHz,
and not 23 or 25.

Have fun.

--Mac

 

[[email protected]]

The xdcrs are piezo crystals - they don't know if they are transmitting
or receiving. If you apply a voltage the crystal will deflect,
producing a physical deformation. If the crystal is deflected by an
external force it will produce a voltage output.

If have designed circuits where these xdcrs were used as both - and it
worked well. Virtually all depth finders use a single xdcr, and they
also work well.

 

[James Meyer]

James Meyer wrote...

What're some examples of not being able to use 'em for transmitting?

There are ultrasonic microphones (receiving) that are either too small
or too delicate to get any reasonable output from when used as a transmitter.

Not all transducers are piezo disks.

Jim

 

[Brian]

Hi...
I've come across some surplus 24KHz transducers and wanted to know if it
is possible to use them for either transmitting AND receiving. I tried
some internet searching, but was never able to get a definate answer. It
seems that vendors sell some which are meant for receiving and some for
transmitting. However, I remember, sometime in the past reading where you
COULD use a transducer as both receiver and transmitter.
Your thoughts would be appreciated.

Thanks,
Jim

Some can be both. But many varieties have one of each and using them for the
opposite part works for poo. I have played with many. All the cheapy T/R
pair type are best used n pairs.