So far I understand that Sensitivity of the transducer is defined as the ratio of its electrical output to mechanical input.
While going through ultrasonic transducer specs, they have a rated sensitivity e.g. -25db/V/uBar
The sensitivity of a microphone can certainly be written as so-many dBV/Pa or so-many dBV/uBar so maybe you have one too many "/" in your data sheet.
For instance 0 dBV is precisely 1 V RMS and -25dBV is 56.2mV RMS so this hopefully answers the first part of the formula.
Sound pressure level is usually quoted in dB but when it comes to specifying microphone sensitivities pascals or Bars are used as representative of the RMS pressure.
For instance an SPL of 94 dB is 1 pascal and 1 pascal also equals 0.00001 bar. 1 uBar is therefore 0.1 pascals. Remember these are RMS values of sound pressures.
EDITED above because wrong mV stated for -25dBV
The expression -25dB/V/uBar means that the output level is 25 dB below a volt per ubar (microbar). This means that the microphone will output a level of -25dB below a volt (0.0562 volts) for an acoustic input of 1 microbar. Note that the micropascal has replaced the microbar as the unit of acoustic pressure. One microbar is equal to 100,000 micropascals. So the microophone sensitivity can also be expressed as -125 dB/V/uPa. Also,note that the reference level for air acoustics is 20 micropascals. So an acoustic level of 94 dB is equivalent to 50119 X 20 or about 1,000,000 micropascals. Note that a micropascal is a relatively small unit. The range of human hearing is about 0 dB to 120 dB. More information about air and human hearing can readily be found with simple searches.
