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.