[SOLVED] Ultrasonic transducer (Murata MA40S4S) input source

[HuyQuoc]

Hello everyone,

I'm working on driving the the Murata MA40S4S ultrasonic transducer, which is a transmitter. I' ve generated the driving signal, which is 40 kHz continuous square wave. The question is how can I drive one transducer with the input signal cause there are only two legs for input as in the datasheet? I wonder if they are the voltage source and the ground.

Thank you for reading this topic.

 

[KlausST]

Hi,

from datasheet I see there is a
* MA40S4S (Sender), two connections
* MA40S4R (Receiver), two connections
both are in the same package.

Klaus

 

[HuyQuoc]

Thanks @KlausST
Could you please tell me more clearly? As I read, the transducer requires driving input signal. So where am I supposed to input this and what parameters do the two connections refer to ?

Huy

 

[KlausST]

Hi,

Connect the driving signal to the sender "S".
Inside is a simple piezo with two connections.
It needs one wire for signel/power input and one wire for signal/power return.

It is unpolarized, so feel free to connect the two wires like you want.
(like a resisor or a incandescent lamp)

Klaus

 

[FvM]

I believe your question is verbosely answered in the datasheet and application notes. You can drive the transducer either single-ended (signal gnd) or differentially (signal+ signal-) as you like.

 

[c_mitra]

It is just a ceramic disk and the two surfaces have been coated with a thin gold film by evaporation for making electrical contact. The ceramic is piezoelectric, that means when a voltage is applied there is a material stress produced that in turn causes a strain. This causes a natural vibration (oscillation). If you are using it as an ultrasonic transducer, you need to include it in the oscillator feedback loop so that resonance is setup and maximum output is obtained. If you force it with a frequency that is not matching with the natural frequency it will still vibrate with reduced power. The same ceramic disk can act as a receiver because if it experiences sound at the natural frequency of the disk, it will produce electrical signal with the same frequency.

The disk is Often symmetrical and either electrode can be used as positive or negative. Because of its ceramic nature, it has very high DC resistance. Sometimes the two electrodes are formed on the same side and that produces bending modes of vibration.