Sensitivity is the lowest level required by a sensor, detector, actuator or material for signal detection and signal storage. The term sensitivity is also used in acoustics for the lowest volume level, for example as a parameter for microphones or amplifiers, as well as in RF technology to determine the lowest received field strength, in optics, where it is the sensitivity of light sensors and the associated spectral photosensitivity, or in magnetic tapes around the strength of the magnetic field so that the hysteresis of the tape material can be used for magnetization.
- In acoustics, sensitivity is determined by radiating a 1 kHz sound signal at one watt from a loudspeaker and measuring the sound pressure level( SPL) at a distance of one meter. This definition is described in IEC 60268-5.
- Headphone sensitivity measurements involve applying a 1-kHz signal of one milliwatt to the headphone and measuring the sound pressure at a dummy head in the ear. This measurement is specified in IEC 60268-7.
- In the microphone sensitivity measurement, a sound pressure of -94 dBSPL (1 Pascal) is applied to the microphone and the output level of the microphone is measured in millivolts/Pascal. This measurement is specified in IEC 60268-4.
- Spectral photosensitivity is a characteristic value of photosensitive devices and components. It can be expressed as the ratio of the number of photons absorbed in a photodiode or image sensor to the electrons emitted from it. Or also as photocurrent in relation to the incident light power.