Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Microphone sensor doubt

  1. Sep 29, 2011 #1
    I have a microphone sensor and when i am reading that datasheet, they have written it in as SENSITIVITY -12mV/Pa. I am not sure, what does it mean. Can someone clear me?
  2. jcsd
  3. Sep 29, 2011 #2


    User Avatar
    Science Advisor
    Gold Member

    It presumably just means that the signal from the microphone will be -12mV per Pascal (i.e. if the sound pressure is 1 Pa it will give you -12 mV, 2 Pa -24 mV).

    For reference: 1 Pa is something like 95 dB (SPL=sound pressure level); i.e. quite loud.
  4. Sep 29, 2011 #3
    I have one more dount that in the same datasheet they have given operating impedance as 5600ohms. What does that mean?
  5. Sep 29, 2011 #4


    User Avatar
    Science Advisor
    Gold Member

    Impedance is the ac equivalent of dc resistance.


    http://hyperphysics.phy-astr.gsu.edu/hbase/electric/imped.html" [Broken]

    also see

    http://en.wikipedia.org/wiki/Electrical_impedance" [Broken]
    Last edited by a moderator: May 5, 2017
  6. Oct 1, 2011 #5
    I desined my circuit with some amplification part after microphone. Here, When i play sound at microphone which gives output as more than 2volts. When there is no input at microphone
    (silent), still the output is between 600mV to 1V. I don't know why this voltage is coming as output even there is no input at microphone.
    My opamp gain is 1000 and it is powerd by single ended with 3V dc. I am using instrumentation 122A amplifiler.
    I thought this was due to powering and gain. Is that right? or am i missing some thing.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook