Dynamic resistance vs temperature measurement for ribbon transducer

[thadman]

I'm interested in doing an experimental analysis of ribbon transducers to contrast with simulations. This data could be made available to the community to aid in transducer development.

A ribbon transducer consists of a rectangular element of metal foil suspended within a magnetic gap and clamped at its ends (ie a clamped-clamped membrane). Current is applied to the foil, which produces an electromagnetic field that interacts with the magnetic field generated by the permanent magnets. The foil bends in response to this force.

A modal analysis could be conducted with the use of a scanning laser vibrometer system. This would appear sufficient for the task.
http://www.polytec.com/usa/158_918.asp

A dynamic resistance vs temperature measurement of the foil would appear to be valuable. However, I'm not sure what instrumentation would be required or how to set up such an experiment.

Any thoughts?

 

[berkeman]

I'm interested in doing an experimental analysis of ribbon transducers to contrast with simulations. This data could be made available to the community to aid in transducer development.

A ribbon transducer consists of a rectangular element of metal foil suspended within a magnetic gap and clamped at its ends (ie a clamped-clamped membrane). Current is applied to the foil, which produces an electromagnetic field that interacts with the magnetic field generated by the permanent magnets. The foil bends in response to this force.

A modal analysis could be conducted with the use of a scanning laser vibrometer system. This would appear sufficient for the task.
http://www.polytec.com/usa/158_918.asp

A dynamic resistance vs temperature measurement of the foil would appear to be valuable. However, I'm not sure what instrumentation would be required or how to set up such an experiment.

Any thoughts?

Could you please say a bit more about the practical applications that would use this type of sensor? Is it used in particle accelerators or plasma fusion confinement field measurements or something? Why does the temperature variable come into play? Is this sensor normally used for static field measurements, or does it have to have some frequency response capability?

 

[thadman]

Could you please say a bit more about the practical applications that would use this type of sensor? Is it used in particle accelerators or plasma fusion confinement field measurements or something? Why does the temperature variable come into play? Is this sensor normally used for static field measurements, or does it have to have some frequency response capability?

A ribbon transducer is used as a microphone and/or loudspeaker. Here is a diagram of a ribbon microphone: http://www.shurenotes.com/issue37/images/images/article1_13.gif

Assuming it is used as a loudspeaker, current is applied to the foil to create sound pressure. The loudspeaker is <10% efficient due to the poor membrane-fluid coupling, which results in a majority of the energy being converted to heat. Resistance increases with temperature, which results in clipping of the waveform. I'd like to measure this effect.