Sensitivity (electronics)

The electroacoustic sensitivity BE a sound sensor, the sensitivity (English responsivity ), with which the sound pressure microphones - these are sound receiver and sensors - into electrical signal voltage ( modulation voltage) is changed. The sensitivity is often referred to in the data sheets as a field - operating gain or field - idling transmission factor and is - unless otherwise stated - for the frequency of 1 kHz.

The factor BE represents the ratio is between the generated electric alternating voltage U and the sound pressure p at 1 kHz, expressed in mV / Pa and is regarded as an essential quality mark of electroacoustic transducers:

The higher the gain, the larger it grows electrical output voltage U at the microphone at a constant sound pressure p at the entrance. The conventional BE value of a condenser microphone is approximately 10 mV / Pa and at a dynamic microphone with approximately 0.5 mV / Pa significantly lower.

Information in the U.S.

In the U.S., the transmission factor z.T. not specify in the SI unit mV / Pa, but as sensitivity, the dB values ​​are negative in dB or in being.

Usual information, depending on the selected reference value:

  • Condenser Microphone: about -40 dB or -60 dB
  • Dynamic microphone: -66 dB or -86 dB as

Reference values:

  • Sound pressure p = 1 Pa corresponds to a sound pressure level of 94 dB SPL = Lp ( 1 Pa → 94 dB SPL ).
  • Sound pressure p = 1 dyn / cm ² corresponds a sound pressure level of Lp = 74 dB SPL ( 1 Pa → 74 dB SPL ).

Transfer factor in amplifiers

If an amplifier is the gain or the gain is defined as the ratio of output and input voltage:

This definition does not require a reference measurement, since the input and output have identical units.

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